Clinical applications have been found for lasers in a number of medical and surgical specialties. New applications in current areas of use and extension of laser technology to other medical and surgical specialties will continue to occur as investigational uses are pursued. Lasers produce medical and surgical effects in target tissues by heating them to the point of coagulation or vaporization, by ionizing molecular tissue, and by inducing photochemical effects through a mediating photosensitizer. Increased ability to transmit certain laser beams via fiber optics further extends areas of clinical application. Laser safety programs are essential to safeguard physician operators, ancillary personnel, and patients. Federal regulation, under two laws, deals with the laser radiation safety of devices and controls to ensure that devices reaching the market are reasonably safe and effective for their intended use.

We assessed the extent to which studies of the association between breast-feeding and infection met four important methodological standards that relate to both the scientific validity and the generalizability of the studies. Of the 20 studies (14 cohort, six case-control), only six met three or four of the methodological standards. Four of these six studies found that breast-feeding was not protective against infections and two found that breast-feeding was protective against infections. In the three studies in which statistical adjustments were made for three additional potentially important confounding variables--size of the family, smoking of cigarettes by the mother, and the mother's level of education-the apparent protective effect of breast-feeding against respiratory tract infections disappeared after the adjustments were made. We found that most of the studies have major methodological flaws that may have compromised their conclusions. The studies that met important methodological standards and controlled for confounding variables suggest that breast-feeding has at most a minimal protective effect in industrialized countries.

In recent years, an extensive medical literature has accumulated regarding the health hazards associated with boxing. As the evidence that boxing produces irreversible brain damage in boxers has become more compelling, physicians have begun to consider the larger issue of whether the sport is acceptable in its present form. This has resulted in a number of proclamations concerning boxing by various representatives of the medical community, which have both added information to and fueled the public debate over boxing. This article seeks to review the relevant medical literature concerning the health effects of boxing; to look at the contributions made in the last few years by the medical community to the public debate over boxing; and to suggest ways in which the objectives of the medical professional concerning boxing can best be achieved.

With the advent of sexually transmitted infections for which curative therapy is not available, primary prevention has assumed greater importance. The spectrum of sexually transmitted diseases (STDs) has broadened, and clinicians need to understand the mechanisms of their transmission and prevention. Modifying selection of sexual partners and avoiding certain sexual practices should theoretically reduce the risk of infection. Clinical and laboratory studies indicate that the use of condoms, diaphragms, and spermicides reduces the risk of acquiring certain infections. At present, hepatitis B is the only STD for which a safe, effective vaccine is available. Use of oral antibiotics cannot be recommended. Postcoital washing or urination have not been shown to have a protective effect against infection. Because of the potential benefits, persons at risk for STDs should be encouraged to modify their sexual behavior and use barrier methods and spermicides to protect themselves against sexually transmitted infections.

Since the treatment of chancroid was reviewed in 1982, the results of subsequent treatment trials have offered the clinician additional therapeutic choices as well as shorter courses of therapy. Erythromycin (500 mg four times a day for seven days) provides consistently effective treatment for cases acquired throughout the world, although erythromycin-resistant strains have been isolated in Singapore. Sulfamethoxazole and trimethoprim (800 mg/160 mg orally twice a day for seven days), ceftriaxone (250 mg intramuscularly one time), and amoxicillin/clavulanic acid (500 mg/125 mg orally three times a day for seven days) are also efficacious. There is, however, significant geographic variability in the susceptibility of Haemophilus ducreyi to sulfamethoxazole and trimethoprim, suggesting this combination may become increasingly less effective, and a lack of in-depth experience in the treatment of chancroid with ceftriaxone and amoxicillin/clavulanic acid.

Tetracycline hydrochloride, 500 mg orally four times a day for seven days, remains the treatment of choice for C trachomatis infections in men and nonpregnant women. Either erythromycin, 500 mg orally four times daily for seven days, or an equivalent dosage of another erythromycin product is an alternative treatment for patients who cannot tolerate tetracycline and for pregnant women. These two treatment regimens can be generalized to include nongonococcal urethritis and mucopurulent cervicitis. However, other treatment regimens that are effective against C trachomatis may not be effective for treating nongonococcal urethritis or mucopurulent cervicitis not caused by C trachomatis. The optimal treatment for pregnant women with C trachomatis infections and women with acute PID has not been established. Additional treatment trials with both groups of patients are needed to determine the effectiveness of antimicrobial agents in addition to those currently used, to establish the appropriate dose of each antimicrobial agent, and to clarify the appropriate duration of treatment. All individuals who are sexual partners of patients with nongonococcal urethritis, mucopurulent cervicitis, and acute PID (within the 30 days prior to onset of their symptoms or time of positive clinical evaluation findings) should be examined for sexually transmitted disease and treated promptly with a regimen effective against uncomplicated gonorrhea and chlamydial infections. Prompt treatment of sexual partners reduces the rate of treatment failure due to reinfection, reduces the transmission of infection, and reduces the frequency of occurrence of adverse sequelae of infection.

Recent clinical trials indicate that reduction of plasma cholesterol concentrations in individuals with increased levels of low-density lipoproteins reduces their risk of myocardial infarction and death. Therefore, the question of "whether to treat" should be shifted to "whom to treat" and "how best to treat". The understanding of normal lipid transport via the plasma lipoproteins has grown to a sophisticated level over the past 20 years. Plasma cholesterol, required for cellular membrane integrity, and plasma triglycerides, the primary mammalian energy source, are carried in lipoprotein particles that vary in size, density, lipid composition, and apolipoprotein content. Some lipoprotein particles (low-density lipoproteins) play a causal role in the atherosclerotic process, while other particles (high-density lipoproteins) appear to prevent this process. Utilizing this understanding of the plasma lipoproteins, a systematic approach to the management of the patient with hyperlipoproteinemia has been developed which may lead to the normalization of plasma lipoprotein concentrations in the majority of hyperlipoproteinemic patients.

Although the cesarean section rate has increased steadily for the past 12 years, further increase seems unlikely since the indications for performing the operation are already broadly defined. Most of the earlier indications will remain unchanged (eg, the presence of placenta previa and cephalopelvic disproportion). The trend toward vaginal delivery in perhaps 30% to 40% of breech births will probably have no material effect on the number of cesarean sections performed, and the present use of cesarean section for multiple pregnancy will probably continue. The two conditions under which cesarean section rates might become significantly lower are (1) automatic repeat cesarean section (which now accounts for more than 25% of all cesarean sections), a procedure which will probably decline as increasing numbers of such women have vaginal deliveries, and (2) a redefinition of the present midforceps classification, which will permit some of the easy midforceps deliveries from a low level to be performed without the legally abhorrent stigma of mid-forceps delivery. The value of prophylactic antibiotics for women predisposed to infection has now been proved, and further placebo studies to demonstrate this are not warranted. In the past, "type and match 2 units" was a routine prelude to cesarean section, and for every unit of blood transfused to cesarean section patients, some 25 units were cross-matched and held in (unnecessary) readiness. This formula is gradually giving way to type and screen, eliminating countless crossmatches. Because of possible harmful fetal effects, preoperative fluid loading, a necessary part of conduction anesthesia, is changing from the customary 5% glucose to the use of fluids containing no glucose. It has been suggested that conduction anesthesia may not offer unlimited time for cesarean section, as used to be thought. Apgar scores are lower if the time from uterine incision to delivery is longer than three minutes, a diminution that may be a function of the anesthesia or may reflect difficulty in delivery. Cesarean section mortality is much lower than it was in former years, but one may expect from one to two deaths per 1,000 operations. Overall, the maternal mortality from cesarean section per se is probably from three to five times higher than that of vaginal delivery (in one series, 11.5 times higher than vaginal delivery). The incidence of mild, transient respiratory signs in the newborn is higher after cesarean than after vaginal delivery, and the incidence of respiratory distress syndrome is also slightly higher.(ABSTRACT TRUNCATED AT 400 WORDS)

Many athletes believe that habitual exercise protects them against infection. This article reviews ten studies of the effects of exercise on various host-defense factors. Exercise produced a transient granulocytosis and lymphocytosis, and in some studies, lymphocyte function was reported to have been enhanced. Serum immunoglobulin and complement levels were not significantly altered in the small number of subjects studied. Two recent studies showed that exercise produced an increase in circulating endogenous pyrogen in man. Since it now appears that endogenous pyrogen is identical to interleukin-1, a product of mononuclear cells that enhances lymphocyte function, it may play a role in host defense. Further studies will be needed before it can be concluded that exercise effects the host response to infection in any clinically meaningful way.

In recent years, the use of the MAST suit has become commonplace. While no controlled human studies have shown the device's efficacy, extensive clinical experience suggests that it is practical and useful in combating shock, stabilizing fractures, and promoting hemostasis. Studies indicate that the antishock trousers elevate blood pressure primarily by increasing peripheral vascular resistance. Proper application and removal of the device are crucial. A number of potential complications exist, but are infrequent and rarely should preclude MAST suit use. Further studies are necessary to prove the efficacy of the device and clearly define its role in patient management.