Brain penetration effects of microelectrodes and DBS leads in STN or GPi.

OBJECTIVE: To determine how intraoperative microelectrode recordings (MER) and intraoperative lead placement acutely influence tremor, rigidity, and bradykinesia. Secondarily, to evaluate whether the longevity of the MER and lead placement effects were influenced by target location (subthalamic nucleus (STN) or globus pallidus interna (GPi)). BACKGROUND: Currently most groups who perform deep brain stimulation (DBS) for Parkinson disease (PD) use MER, as well as macrostimulation (test stimulation), to refine DBS lead position. Following MER and/or test stimulation, however, there may be a resultant "collision/implantation" or "microlesion" effect, thought to result from disruption of cells and/or fibres within the penetrated region. These effects have not been carefully quantified. METHODS: 47 consecutive patients with PD undergoing unilateral DBS for PD (STN or GPi DBS) were evaluated. Motor function was measured at six time points with a modified motor Unified Parkinson Disease Rating Scale (UPDRS): (1) preoperatively, (2) immediately after MER, (3) immediately after lead implantation/collision, (4) 4 months following surgery-off medications, on DBS (12 h medication washout), (5) 6 months postoperatively-off medication and off DBS (12 h washout) and (6) 6 months-on medication and off DBS (12 h washout). RESULTS: Significant improvements in motor scores (p<0.05) (tremor, rigidity, bradykinesia) were observed as a result of MER and lead placement. The improvements were similar in magnitude to what was observed at 4 and 6 months post-DBS following programming and medication optimisation. When washed out (medications and DBS) for 12 h, UPDRS motor scores were still improved compared with preoperative testing. There was a larger improvement in STN compared with GPi following MER (p<0.05) and a trend for significance following lead placement (p<0.08) but long term outcome was similar. CONCLUSION: This study demonstrated significant acute intraoperative penetration effects resulting from MER and lead placement/collision in PD. Clinicians rating patients in the operating suite should be aware of these effects, and should consider pre- and post-lead placement rating scales prior to activating DBS. The collision/implantation effects were greater intraoperatively with STN compared with GPi, and with greater disease duration there was a larger effect.

AIDS in Africa: an epidemiologic paradigm.

Cases of the acquired immune deficiency syndrome (AIDS) have been reported in countries throughout the world. Initial surveillance studies in Central Africa suggest an annual incidence of AIDS of 550 to 1000 cases per million adults. The male to female ratio of cases is 1:1, with age- and sex-specific rates greater in females less than 30 years of age and greater in males over age 40. Clinically, AIDS in Africans is often characterized by a diarrhea-wasting syndrome, opportunistic infections, such as tuberculosis, cryptococcosis, and cryptosporidiosis, or disseminated Kaposi's sarcoma. From 1 to 18% of healthy blood donors and pregnant women and as many as 27 to 88% of female prostitutes have antibodies to human immunodeficiency virus (HIV). The present annual incidence of infection is approximately 0.75% among the general population of Central and East Africa. The disease is transmitted predominantly by heterosexual activity, parenteral exposure to blood transfusions and unsterilized needles, and perinatally from infected mothers to their newborns, and will continue to spread rapidly where economic and cultural factors favor these modes of transmission. Prevention and control of HIV infection through educational programs and blood bank screening should be an immediate public health priority for all African countries.

AIDS: an international perspective.

The acquired immunodeficiency syndrome (AIDS) and infection with the human immunodeficiency virus type 1 (HIV-1) constitute a worldwide public health problem. Whereas in Europe and in most of the Americas transmission of HIV-1 has occurred predominantly among homosexual men and intravenous drug abusers, in Africa a distinct epidemiologic pattern has emerged that indicates that HIV-1 infection is mainly heterosexually acquired. Heterosexual transmission appears to be increasing in some parts of Latin America and the Caribbean, and possibly in the United States. In addition to HIV-1, at least one other human retrovirus, namely HIV-2, has been implicated as a cause of AIDS in Africa and Europe. Factors that influence heterosexual transmission of HIV-1 include genital ulcerations, early or late stages of HIV-1 infection in the index case, and possibly oral contraception and immune activation. The rate of perinatal transmission is enhanced when the mother's illness is more advanced. AIDS and HIV-1 infection may have a significant impact not only on public health, but also on the demography and socioeconomic conditions of some developing countries. Programs for the prevention and control of AIDS should be an immediate priority in all countries.

Myocardial magnesium depletion associated with prolonged hypomagnesemia: a longitudinal study in heart transplant recipients.

OBJECTIVES: This study was carried out to establish prospectively the incidence and relation of hypomagnesemia and myocardial magnesium depletion after heart transplantation. BACKGROUND: No serial in vivo study of the relation of serum with tissue magnesium has been described. Myocardial magnesium depletion is associated with intracellular calcium overload, an increased incidence of cardiac arrhythmia and changes in coronary vasculature similar to those seen in the accelerated atherosclerosis that compromises graft survival after transplantation. METHODS: In a prospective study in 19 consecutive patients, serum and myocardial magnesium content were measured serially for 9 months after heart transplantation. Blood cyclosporine was assayed simultaneously. RESULTS: The incidence of hypomagnesemia was 100% during the 9-month study period, with lowest levels at 3 months (mean 0.80 vs. 0.64 mmol/liter, p less than 0.002). Myocardial magnesium depletion developed in 94% and was persistent in 55%; the lowest levels occurred at 6 months (mean 33.6 vs. 30.1, mumol/g, p less than 0.04). Hypomagnesemia predated decreases in myocardial magnesium by 2 to 6 weeks. Peak cyclosporine levels correlated positively with the decrease in serum magnesium. Clinical events were rare. CONCLUSIONS: This is the first report of serial measurement of tissue magnesium. Persistent hypomagnesemia is invariably accompanied by myocardial magnesium depletion in the transplanted heart. Reciprocal calcium overload and adverse changes in coronary vasculature would be expected from previous studies and merit further investigation. Should the implications of this study extend to the native heart, myocardial magnesium depletion may contribute to the high incidence of fatal arrhythmic events observed in patients with heart failure, who commonly have persistent hypomagnesemia.

The global patterns and prevalence of AIDS and HIV infection.

PIP: This update on world prevalence of HIV infections and patterns of transmission begins with definitions of AIDS, and an evaluation of efficiency of reporting, and ends with tentative projections and global impact of the pandemic. In developed countries the CDC/WHO clinical and serological definition of AIDS as formulated in 1985 and modified in 1987 is used, but in rural Africa the WHO clinical definition of AIDS is appropriate. AIDS reporting has improved, and is considered 80% complete from the U.S. Reporting is variable among some European and Latin American countries, and is only preliminary in Eastern Europe, Middle East, Asia and the Pacific. Estimates of 10-20% reporting in Africa is given. About 250,000 cases are probably ongoing. ELISA tests are now considered very accurate. Global transmission patterns fall into 3 classes: I. homosexual and bisexual men, iv drug users, their partners, with a male to female ratio of 10-15:1, in industrialized countries. Here overall prevalence is 1%, but may be as high as 50% susceptible groups. Pattern II. heterosexuals, sex ratio 1:1, common perinatal transmission, significant transmission by syringes and blood products, in Central and Eastern Africa and parts of the Caribbean and Latin America. Pattern III. both homosexuals and heterosexuals, infected after mid-1980s, most cases transmitted by foreign travellers, some by imported blood products, in Eastern Europe, North Africa, the Middle East, Asia and the Pacific Islands excluding Australia and New Zealand. WHO estimates that up to 10 million people are already infected with HIV, and that by 1991 1 million will develop AIDS. The average incubation time is 8-9 years. The majority of cases will appear within 4-5 years. Since most cases are adults aged 20-49 years, and many are urban, more educated adults, economic and political destabilization may be possible in some areas.^ieng

HIV infection and associated risk factors in female prostitutes in Kinshasa, Zaire.

In Africa, female prostitutes represent a high risk group for HIV infection. In Kinshasa, Zaire, 101 (27%) out of 377 prostitutes were seropositive to HIV by ELISA and Western blot determination. Seropositivity was significantly associated with the number of lifetime partners with a median number of 600 partners, four seropositives and 338 for seronegative individuals (P = 0.02). Seropositivity was also significantly associated with a history of taking oral medications for the prevention of sexually transmitted diseases and/or pregnancy (odds ratio = 2.21, confidence interval = 1.2-4.2), and with the introduction of any product into the vagina for hygiene or other purposes (odds ratio = 2.3, confidence interval = 1.1-4.7). In addition, among 85 prostitutes reporting condom use by their sexual partners during the previous year, the use of condoms by 50% or more of partners was associated with a reduced risk of HIV seropositivity (P = 0.046). An increased risk of HIV seropositivity was not associated with fellatio, anal intercourse, or with any type of kissing. Twenty-nine per cent of prostitutes reported at least one symptom suggestive of HIV infection, and seropositivity was associated with weight loss, either with or without chronic diarrhea or pruritic dermatitis. These data confirm that African prostitutes are at high risk for HIV infection and that the number of lifetime sexual partners, and factors which interfere with the integrity of the vaginal or cervical mucosa, may be associated with an increased risk of HIV infection acquired through heterosexual contact.(ABSTRACT TRUNCATED AT 250 WORDS)

Generalized papular pruritic eruption in African patients with human immunodeficiency virus infection.

Of 284 patients hospitalized with HIV infection, 52 (18%) presented with a generalized pruritic papular eruption. No significant association between this eruption and other HIV manifestations or any opportunistic infection was found. Fifty-three of 61 (87%) consecutive African patients referred for a generalized papular pruritic eruption of unknown etiology of at least 1 month's duration were HIV seropositive, including 15 (65%) of 23 in good general condition. Thirty-seven (95%) of 38 patients with this eruption and severe weight loss (greater than 10% of normal body weight) were seropositive. The initial skin lesions were small, firm, intensely pruritic papules which released a small drop of clear fluid when scratched. Scratched papules became later hyperpigmented macules. Lesions were symmetrically distributed over the body and were most frequently found on the extensor surfaces of the arm, the dorsal surface of the hands, the inferior part of the legs, the ankles and the dorsum of the feet. Histologic examination showed a non-specific inflammatory reaction. Thirty-three (51%) patients reported that the skin eruption was their initial disease manifestation. In African patients, the presence of an unexplained generalized pruritic papular eruption is highly indicative of HIV infection.

Equine antitoxin use and other factors that predict outcome in type A foodborne botulism.

The use of trivalent equine antitoxin in treating foodborne botulism has not been adequately assessed. One hundred thirty-two cases of type A foodborne botulism reported to the Centers for Disease Control in the period from 1973 to 1980 are reviewed to evaluate the effect of antitoxin therapy and other factors on the outcomes of patients with botulism. The fatality rates were higher in patients over 60 years old and in those who were index patients (the first or only patient in an outbreak). The clinical course was longer in patients over 60 years old, patients whose incubation period was less than 36 hours, and index patients. Patients who had received trivalent equine antitoxin had a lower fatality rate and a shorter course than those who did not receive antitoxin, even after controlling for age and incubation period. Patients who received antitoxin in the first 24 hours after onset had a shorter course but about the same fatality rate as those who received antitoxin later. These results suggest that trivalent antitoxin has a beneficial effect on survival and shortens the course of patients with type A botulism.

New Haemophilus influenzae type b control strategy: premature commitment to prophylaxis?

Recent promulgation of an official policy on prevention of secondary cases of Haemophilus influenzae type b disease illustrates the challenges and frustrations inherent in the policy-making process. Despite evidence that H influenzae type b disease is "contagious" in households and probably also in day care centers and despite demonstration that rifampin eradicates nasopharyngeal H influenzae type b carriage, the single field study of rifampin use to prevent secondary cases of H influenzae type b disease remains unpublished and has yet to receive broad critical scrutiny. Promulgation of the rifampin strategy prior to publication of this critical study is unfortunate, as public and private providers are now committed to a policy that will be difficult to evaluate or alter. Now that the strategy has been issued, the central question regarding rifampin prophylaxis has changed from "Is this strategy effective?" to "Can this strategy be shown to be ineffective?" When policies are issued prior to publication of key supporting data, or when such studies are either missing or highly controversial, the policy-making committee might publish, along with its recommendations, explicit criteria for continuation, modification, or withdrawal of the new policy. This structured reassessment approach could accommodate the critical need to proceed with disease control recommendations--even though based on incomplete information--yet underscore the policy's tentative nature and provide direction for future assessment and study.

Pediatric plague.

The large reservoir of animal plague in the American West led to 121 cases of human plague from 1970 to 1980. The majority (55%) of recent cases have occurred in children 16 years of age and younger. In New Mexico 38 pediatric plague cases were reviewed to determine the epidemiologic, clinical, and laboratory feature of this disease. Thirty-one patients (82%) had bubonic plague and seven (18%) had primary septicemic disease. Primary septicemic plague had a significantly higher case-fatality ratio (71% vs 3%; P = .0002) and an increased risk of plague pneumonia (57% vs 6%; P = .01) compared with bubonic disease. Symptoms at onset, physical examination, and laboratory data at hospitalization (mean of three days after onset) were consistent with an acute, systemic febrile illness. Recovery from plague was slow, requiring an average of 5.9 days from initiation of effective antibiotics until fever lysis. Only a minority of plague patients were initially suspected to have plague, even by the time of hospitalization. Whereas clinical evidence, particularly in bubonic disease, should suggest plague, residing in or visiting a rural are of the West (especially from June through September) during the week prior to illness may be the only useful epidemiologic clue for the majority of patients who lack a history suggestive of exposure to animals or fleas. The importance of pediatric plague stems from the recent increase in cases, the significant increase in the proportion of all cases occurring in children, the public health implications of plague pneumonia (16% of cases), and the demonstrated potential for plague patients to travel to areas of the country unfamiliar with the disease and its sylvatic home in the American West.

Human immunodeficiency virus seroprevalence in pediatric patients 2 to 14 years of age at Mama Yemo Hospital, Kinshasa, Zaire.

Seroprevalence to human immunodeficiency virus (HIV) was determined among 368 children 2 to 14 years of age who were admitted to the pediatric service at Mama Yemo Hospital in Kinshasa, Zaire. Forty (11%) of these patients and only one (1%) of 92 healthy siblings of these patients were HIV seropositive (chi 2 = 8.68, P less than .01). Seropositivity was associated with previous hospitalization, receipt of a blood transfusion prior to the current hospitalization (odds ratio 3.1; 95% confidence interval, 1.5 to 6.4), receipt of medical injections during the past year, and smaller household size. Clinically, HIV seropositivity was associated with the diagnoses of malnutrition and pneumonia. A higher proportion of seropositive children died during the current hospitalization (4/40 v 10/328); when patients with malaria were excluded, the in-hospital mortality of seropositive children was more than eight times higher than that of seronegative children (Fisher exact test, P = .006). Clarification of clinical, immunologic, and epidemiologic features of childhood HIV infection is urgently required because HIV appears to account for or complicate a substantial proportion of pediatric hospitalizations in Kinshasa.

Cardiac morphologic observations after operative closure of acquired ventricular septal defect during acute myocardial infarction: analysis of 16 necropsy patients.

Certain cardiac morphologic findings are described in 16 necropsy patients having operative closure of an acquired ventricular septal defect (VSD) during acute myocardial infarction (AMI). Of the 16 patients, 6 were women (mean age 69 +/- 7 years) and 10 were men (mean age 60 +/- 11 years). The AMI associated with the VSD was the first coronary event in 13 patients (81%). At least 6 patients had a history of systemic hypertension. Conduction disturbances were diagnosed by electrocardiogram in 5 patients (31%). The median interval from the onset of the AMI to death was 11 days, and from the onset of the AMI to operative closure of the VSD, 4 days. Eight patients died in the operating room or within 2 hours of operation. Coronary artery bypass grafting was performed simultaneously with the VSD closure in 7 patients. Death was attributed to unsuccessful VSD closure in 5 patients, to inadequate left ventricular cavity after resection of necrotic myocardium in 5 patients and to inadequate viable left ventricular myocardium in 4 patients. Heart weights were increased in 14 patients (88%). The AMI associated with the VSD was anterior in 9 patients and posterior (inferior) in 7. Healed myocardial infarcts were present in 3 patients. All 16 patients had severe (greater than 75% in cross-sectional area) narrowing of 1 or more of the 4 major epicardial coronary arteries.

Rupture of the left ventricular free wall during acute myocardial infarction: analysis of 138 necropsy patients and comparison with 50 necropsy patients with acute myocardial infarction without rupture.

Clinical and necropsy findings in 138 patients (69 men and 69 women) with rupture of the left ventricular (LV) free wall during acute myocardial infarction (AMI) (rupture group) were compared with 50 patients who died during their first AMI without rupture (nonrupture group). The frequency of systemic hypertension (55 vs 52%), angina pectoris (13 vs 22%) and congestive heart failure (0 vs 0%) before the fatal AMI was similar for both rupture and nonrupture groups. Mean heart weights for men (479 vs 526 g) and women (399 vs 432 g) with and without rupture also were insignificantly different. LV scar before the infarct that ruptured was present in 18 patients (13%); previous necropsy studies of fatal AMI without rupture have indicated that 50% have LV scars. The rupture group had a significantly more frequent (p less than 0.01) lateral wall location of the infarct (12 vs 2%). The number of 3 major (right, left anterior descending and left circumflex) epicardial coronary arteries narrowed at some point greater than 75% in cross-sectional area by atherosclerotic plaque was significantly lower (p less than 0.01) in the rupture group (39 vs 58%). The percent of these 3 arteries totally occluded or nearly so (greater than 95% in cross-sectional area) by plaque also was significantly less (p less than 0.001) in the rupture group (24 of 198 arteries [12%] vs 38 of 144 arteries [26%]). Analysis of each 5-mm long segment of these arteries in each group disclosed that the rupture group had significantly less narrowing than the nonrupture group. Of the 3,287 five-mm segments of artery examined in the rupture group (66 patients), 512 (15%) were narrowed greater than 75% in cross-sectional area by plaque; in contrast, of the 1,848 five-mm segments in the nonrupture group (38 patients), 508 (28%) were narrowed to this degree by plaque (p less than 0.0001). Thus, rupture of the LV free wall primarily is a complication of the first AMI and is associated with considerably less amounts of coronary narrowing than fatal AMI without rupture.

Acquired ventricular septal defect during acute myocardial infarction: analysis of 38 unoperated necropsy patients and comparison with 50 unoperated necropsy patients without rupture.

Thirty-eight patients (24 men and 14 women) with an acquired ventricular septal defect during acute myocardial infarction (AMI) (rupture group) were studied and their clinical and necropsy findings were compared with 50 patients who died during their first AMI without rupture (nonrupture group). The frequency of systemic hypertension (54 vs 52%), angina pectoris (28 vs 22%) and congestive heart failure (5 vs 0%) before the fatal AMI was similar for both rupture and nonrupture groups. Mean heart weights for men (498 vs 526 g) and women (397 vs 432 g) with and without septal rupture also were insignificantly different. Whereas previous studies of fatal AMI cases have shown that 50% of cases of fatal AMI without rupture have left ventricular scars, only 4 (10%) of the rupture cases had a left ventricular scar before the infarct that ruptured. The rupture group had a significantly more frequent (p less than 0.01) posterior location of the infarcts (74 vs 40%) and, therefore, a higher frequency of associated right ventricular infarcts 50 vs 18%). The number of 3 major (right, left anterior descending and left circumflex) epicardial coronary arteries narrowed at some point greater than 75% in cross-sectional area of atherosclerotic plaque was the same in both groups. The percent of these 3 arteries totally occluded or nearly so (greater than 95% in cross-sectional area) by plaque was significantly less (p less than 0.001) in the rupture group compared with the nonrupture group (9 of 99 arteries [9%] vs 38 of 144 arteries [26%]).(ABSTRACT TRUNCATED AT 400 WORDS)

Nonbronchoscopic lung lavage for diagnosis of opportunistic infection in AIDS.

Thirty patients known to have or suspected of having acquired immunodeficiency syndrome (AIDS) were evaluated for opportunistic pulmonary infection using a double lumen lavage catheter (DLL). Lavage specimens obtained were cytocentrifuged and initially stained by the Papanicolaou technique as a means of rapid evaluation for Pneumocystis carinii. If no opportunistic organism was identified, the patient underwent further diagnostic investigations. In 18 patients receiving mechanical ventilatory support, the procedure was performed via the endotracheal tube. Twelve patients who were less severely ill underwent the procedure via the transnasal route. In 43 percent (13/30), opportunistic infections were diagnosed by DLL. Twelve had P carinii, one of whom had cytomegalovirus and another of whom had Herpes simplex viruses, and one with Toxoplasma gondii. Thus, the sensitivity for all opportunistic infections was 86 percent (12/14). The volume of fluid recovered averaged 93 percent of that instilled. There was no significant difference between prelavage and postlavage PaO2. In this group of patients, double lumen lavage obviated the need for more invasive and expensive procedures.

Myocyte nuclear area as a measure of left ventricular hypertrophy in transplant patients.

Transplanted hearts have been reported to increase in size/weight in the first few months after transplant and to remain stable thereafter. An indirect way of assessing the changes in heart weight is through the changes in the area of the myocyte nucleus (MNA). We studied 20 patients who had undergone orthotopic heart transplantation more than 12 months previously; 10 had become hypertensive, and the remaining 10 were normotensive. Myocardial biopsies taken the first week after transplant and 6, 12, 24, and 52 weeks after transplant were assessed. Myocyte nuclear area was measured in 200 myocytes/biopsy with an image analyzer. Individual measurements showed a wide variation in MNA, with significant overlaps among the different biopsies. Assessment of MNA at one year showed increased MNA in 4 10 patients in the hypertensive group and 5 10 in the normotensive group. The remaining patients showed either no statistically significant changes in MNA or a significant (p < 0.0001) decrease in MNA. The presence of systemic hypertension was not a predictive factor for significant hypertrophy and, in some cases, not even for hypertrophy itself. We conclude that although there is often an increase in MNA of the transplanted heart at one year posttransplant, this increase is not systematic, and isolated morphometric results should be viewed cautiously.

Experimental model of left ventricular failure.

A model of chronic cardiac failure has undergone extensive hemodynamic investigation. Under anesthesia the homonymous and second diagonal coronary arteries of sheep have been ligated. The resulting myocardial infarction caused significant acute hemodynamic impairment (paired two-tailed t tests), mean pulmonary artery pressure increasing from 7.31 +/- 0.94 to 13.80 +/- 1.19 mm Hg (p less than 0.001), pulmonary artery diastolic pressure increasing from 4.94 +/- 1.03 to 11.13 +/- 1.27 mm Hg (p less than 0.001), and directly measured left ventricular end-diastolic pressure increasing from 9.31 +/- 1.52 to 17.42 +/- 1.82 mm Hg (p less than 0.001) after infarction documented with invasive monitoring. There was a hemodynamically significant left ventricular aneurysm (paired two-tailed t tests) in animals studied 3 months later, with increased mean pulmonary artery pressure from 7.20 +/- 1.15 to 13.80 +/- 2.00 mm Hg (p = 0.009), an increase in pulmonary artery diastolic pressure from 4.60 +/- 1.30 to 12.10 +/- 2.06 mm Hg (p = 0.006), and an increase in left ventricular end-diastolic pressure from 11.00 +/- 1.94 mm Hg before infarction to 17.00 +/- 2.69 mm Hg (p = 0.038). We conclude that this is a useful model of chronic left ventricular failure that is reproducible and applicable to investigations of therapeutic options in chronic heart failure.

A profile of uncompensated hospital care, 1983-1995.

This DataWatch examines national trends in the provision of uncompensated hospital care. It shows that rapid growth from 1983-1986 was followed by modest growth through 1990, a time during which managed care was becoming established in some regions. There was then another spurt in uncompensated care from 1991-1993, a period that corresponds to sizable increases in disproportionate-share payments. Uncompensated care growth again slowed through 1995. The increase in uncompensated care levels after 1988 appears not to have kept pace with growth in hospital expenses or the number of uninsured. However, the trend data do not suggest a large-scale reduction of effort.

Physicians and medical students: factors affecting entry into public health.

We surveyed members of a recent master of public health (MPH) degree program to learn more about how, when, and why physicians and medical students decided to seek formal training in public health. We interviewed physicians and medical students to determine how and why these MPH students became involved in what they considered public health work; how and why they decided to attend public health school; and what their career plans were following completion of the degree program. All 47 medical students and physicians responded to the survey. Sixty-six percent described previous public health-related work experience. Only 5% decided prior to or during college to attend public health school. A personal contact directed 62% towards public health school. Those with previous public health work experience were more likely to pursue what they considered public health careers after completion of public health school than those without such previous work experience. The continuing need for qualified practitioners and leaders in public health challenges the medical community to characterize further those factors motivating medical students and physicians to formalize their training in public health.