University leadership for innovation in global health and HIV/AIDS diagnostics

Medical products used in the developed world often fail to adequately serve resource-limited settings where electricity, transportation and health care workers are not readily available. We suggest that the problem is not only a lack of coordinated financial resources to purchase existing medical products, but also a lack of products that are specifically designed for resource-limited settings. While donor organisations with a focus on global health are increasingly willing to bear the additional financial risk for the research and development of such high-impact medical products, corporations are still reluctant to take their best scientists and engineers away from more commercially attractive projects. Universities, on the other hand, given their teaching and research missions, are well positioned to engage in such high-risk development projects. A group of biomedical, engineering, business and social science researchers at Northwestern University (NU) propose a creative model to address significant social and health needs. The team's initial product focus is a rapid test for diagnosing infants with HIV. The NU model aligns the incentives and expertise of industry, donors and academia to innovate medical products, such as the infant HIV diagnostic test, for resource-limited settings.

Cardiorespiratory events in preterm infants referred for apnea monitoring studies

BACKGROUND

Episodes of apnea, desaturation, and bradycardia are common in preterm infants. Such infants who have persistent cardiorespiratory events detected by clinical bedside monitoring often are referred for overnight apnea monitoring studies.

OBJECTIVE

To characterize apnea, bradycardia, and desaturation events in infants referred for an overnight apnea monitoring study and compare them with corresponding events in control infants of similar age and weight with no bedside monitor alarms.

METHODS

Twelve-hour bedside apnea monitoring studies were performed on 68 preterm infants before hospital discharge. This population included 35 infants who were referred by their attending physicians because of persistent bedside monitor alarms (referral group) and 33 infants who had no documented cardiorespiratory events for at least 2 days before the study (control group). Each study monitored respiration via respiratory inductance plethysmography, oxygen saturation (Sao2), and heart rate. Events were defined as meeting 1 of the following criteria: apnea > or =20 seconds, bradycardia < or =80 beats per minute, or Sao2 < or =80%.

RESULTS

The incidence of apnea > or =20 seconds was low, with no significant difference between infant groups. Referral infants exhibited a higher occurrence of desaturation episodes (20 +/- 6 vs 6 +/- 3 episodes/12-hour study) and a higher occurrence of bradycardia episodes (4.3 +/- 0.8 vs 1.1 +/- 0.3 episodes/12-hour study) than controls. These episodes of desaturation and bradycardia were always preceded by a respiratory pause, which was shorter in the referral infants (10.0 +/- 0.4 seconds vs 12.0 +/- 1.0 seconds). Baseline Sao2 was lower in referrals than controls (95 +/- 1% vs 98 +/- 1%), and the incidence of periodic breathing was significantly higher.

CONCLUSIONS

Infants referred for apnea monitoring studies because of persistent bedside monitor alarms have very infrequent prolonged apnea but a higher frequency of desaturation and bradycardia in response to short respiratory pauses than infants without persistent bedside monitor alarms. Referral infants also exhibit a lower baseline Sao2. These abnormalities in oxygenation and cardiorespiratory control may be markers for subtle residual lung disease or functional central nervous system abnormalities.

Pathological pancreatic exocrine function and duct morphology in patients with cholelithiasis

Most authors claim alcohol consumption to be the only relevant reason for chronic pancreatitis. However, gallstones might cause this disease, as they do cause acute pancreatitis. In this study 91 gallstone patients and 94 age-matched controls were investigated concerning exocrine pancreatic function (fecal elastase-1 concentrations). Furthermore x-rays of 100 consecutive ERCP patients were evaluated for differences concerning pancreatic duct changes between patients with and without evidence of cholelithiasis. Pathological elastase 1 levels were more frequent in gallstone patients (30,8%) as compared to age-matched controls (19%). Symptoms such as upper abdominal pain, bloating, and fat intolerance were reported more often in gallstone patients. In ERCP of gallstone patients (N = 60), 77% were found to have chronic pancreatitis according to the Cambridge classification, while in nongallstone-patients (N = 32) 47% had chronic pancreatitis. In conclusion, according to these data a pathophysiological connection between gallstones and chronic pancreatitis appears to be probable.

Modulation of hyperoxia-induced TNF-alpha expression in the newborn rat lung by thalidomide and dexamethasone

The effect of high oxygen concentrations on lungs of neonatal rats was studied. In addition, some oxygen-exposed animals were treated with either dexamethasone or thalidomide. No gross histologic changes were noted in the lungs following exposure to 95% oxygen nor were there changes in the total number or the phenotypic distribution of BAL cells obtained from these lungs compared to lungs from air exposed (control) neonatal rats. The majority of the BAL cells were CD45+ leukocytes (macrophages). However, when BAL cells were exposed to LPS in vitro, TNF-alpha production was higher in cells from rats exposed to 95% oxygen compared to cells from rats exposed to ambient air. In addition, lung TNF-alpha and IL-6 mRNA levels were increased after exposure to 95% oxygen. In the lungs of animals treated with either dexamethasone or thalidomide, TNF-alpha mRNA levels were reduced, while only dexamethasone treatment also reduced IL-6 mRNA levels.

[Prevention of radiation-induced diarrhea by smectite. Results of a double-blind randomized, placebo-controlled multicenter study]

PURPOSE

Diarrhea and abdominal pain are well-known side effects abdominal or pelvic of radiation therapy that may lead to interruption of treatment in serious cases. In recent trials the silicate smectite has proven a promising drug in the prophylaxis of these adverse events. The presented trial aimed at the verification of earlier studies and the evaluation of a dose-effect relationship.

PATIENTS AND METHODS

Between April 1994 and May 1995, a total of 176 patients obtaining radiotherapy of the pelvis or the abdomen were evaluated in a double-blind, randomized placebo-controlled investigation regarding the prophylactic effect of smectite (= Colina) against radiotherapy-induced diarrhea. During the whole period of radiotherapy 85 patients obtained 2 x 6 g smectite daily and 91 patients received 2 x 6 g placebo. The primary end point of the analysis was the time to the first appearance of diarrhea (> or = 3 pappy stools).

RESULTS

All 176 patients were evaluated according to an intent-to-treat analysis. There was no significant difference between the prophylactic effects of smectite and placebo. For an explorative post-hoc analysis the total study group was split up into 2 subgroups, one with an irradiated small bowel volume < or = 837.5 ml, the other with a small bowel volume > 837.5 ml (median); the analysis indicated that the first subgroup showed a benefit for the smectite-treated patients in contrast to the placebo treatment (32 vs. 18 calendar days to the first appearance of diarrhea). This benefit was statistically not significant.

CONCLUSION

Prophylactic application of smectite during irradiation of the pelvis and the abdomen can delay the development of radiotherapy-induced diarrhea, a statistical significance could not be verified neither in the total study group nor in the post-hoc subgroup analysis.

Pancreatic exocrine function in patients with type 1 and type 2 diabetes mellitus

Reduced exocrine pancreatic function has been observed in a high percentage of patients with type 1 diabetes in the past. There are only few data for type 2 diabetes available and they are contradictory. In this study we investigated exocrine pancreatic function in 105 controls and 114 patients with type 1 or type 2 diabetes mellitus by means of an indirect test (faecal elastase-1 concentration). This test has good sensitivity and specificity for moderate and severe pancreatic insufficiency as compared to the gold standard. Reduced faecal elastase-1 concentrations were found in 56.7% of type 1 patients, 35% of type 2 patients and 18.1% of the controls. Elastase-1 concentrations did not correlate with alcohol consumption, diabetes duration or diabetes therapy. The data found for type 1 patients correspond to those reported in earlier studies. The results for type 2 diabetics show that exocrine pancreatic function is also impaired in a high percentage in this group of patients. Pathogenetic concepts to explain these findings as consequences of diabetes complications or insulin deficiency are still under debate. Observations from autopsies and the data of the controls in this study suggest that chronic pancreatitis might be a common problem. In consequence, diabetes secondary to exocrine disease could be much more frequent than believed so far.

MP1: a MEK binding partner that enhances enzymatic activation of the MAP kinase cascade

Signal transduction is controlled both by regulation of enzyme activation and by organization of enzymatic complexes with nonenzymatic adapters, scaffolds, and anchor proteins. The extracellular signal-regulated kinase (ERK) cascade is one of several evolutionarily conserved mitogen-activated protein (MAP) kinase cascades important in the regulation of growth, apoptosis, and differentiation. A two-hybrid screen was conducted to identify nonenzymatic components of this signaling cascade that might be important in regulating its activity. A protein called MP1 (MEK Partner 1) was identified that bound specifically to MEK1 and ERK1 and facilitated their activation. When overexpressed in cultured cells, MP1 enhanced activation of ERK1 and activation of a reporter driven by the transcription factor Elk-1. Expression of MP1 in cells increased binding of ERK1 to MEK1. MP1 apparently functions as an adapter to enhance the efficiency of the MAP kinase cascade.

An optical submicrometer calcium sensor with conductance sensing capability

The identification of chemical species and the measurement of their concentrations with high (submicrometer) spatial resolution are of considerable importance in cell biology. In this article we report the first successful development of a > or = 0.1-micron Ca2+ sensor based on a pulled micropipet, filled with a conducting porous sol-gel glass which was doped with the fluorescent calcium green 1 Ca2+ indicator. Such sensors are potentially capable of measuring Ca2+ concentrations as low as 10(-8) M, in confined volumes, with a three-dimensional resolution which exceeds approximately 0.1 micron. A major advantage of the sensor is its capability to be integrated into a multifunctional probe which will measure chemical analyte concentrations and ion conductance.

Effects of increased red cell mass on subclinical tissue acidosis in hyaline membrane disease

AIM

To determine whether there are subclinical deficits in oxygen delivery in ventilated premature neonates.

METHOD

Ventilated premature neonates weighing less than 1500 g, who were transfused for anaemia or who were given colloids for clotting abnormalities (or oedema), were haemodynamically monitored during the first week of life. Calf muscle surface pH (pH) was measured in conjunction with peripheral limb blood flow by occlusion plethysmography.

RESULTS

Packed red blood cell transfusions corrected a subclinical regional tissue acidosis (low tpH) without affecting arterial pH or limb blood flow. This observation also correlated with an increase in regional oxygen delivery. The data were also suggestive of a pattern of pathological, supply dependent, oxygen delivery and are similar to other observations made in adults with adult respiratory distress syndrome.

CONCLUSIONS

Packed red blood cells increase regional oxygen delivery and tissue surface pH. In contrast, colloid infusion provided no substantial cardiovascular or metabolic benefit to these patients and should be avoided when oxygen delivery is at issue and when there may be leaky pulmonary capillaries.

Surfactant therapy prior to the interhospital transport of preterm infants

The risk-to-benefit ratio of surfactant treatment of outborn preterm infants prior, as opposed to after, transportation to a perinatal center is not known. The objective of this study was to document current practice and to examine clinical outcomes in North America. In phase I (December, 1991 to January, 1992) questionnaires were distributed to 114 perinatal centers in the United States and Canada. The centers returned 98 surveys. Over half (50.5%) of the centers report giving surfactant rescue prior to infant transport, but only a minority (9.5%) of the centers report doing so for prophylaxis. In phase II (January, 1992 to December, 1992), clinical outcomes of surfactant-eligible babies requiring interhospital transport at a university hospital were evaluated to determine which infants ultimately received surfactant and when. The infants were compared between groups and did not differ significantly in gestational age, birthweight, sex type, number of multiple births, five-minute Apgar scores, or whether antenatal steroids were used. In phase II, the 66 consecutive, ventilator-dependent, outborn infants with average, and median, gestational age of 28 weeks were compared. The infants receiving surfactant prior to transport, when compared to the infants that got it after transport (9 hours later), did not do any better. There was 6% more survival without bronchopulmonary dysplasia in the group receiving surfactant after transport (65.2% versus 59.3%, p = 0.665). The infants receiving surfactant after transport were off the ventilator sooner (95% C.I. 6.0-28.7 versus 11.8-25.9 days) and discharged from the perinatal center earlier (95% C.I. 37.8-70.8 versus 47.9-69.0 days). Furthermore, arterial blood gases before and after transport reveals that there were no short-term advantages in administering surfactant prior to transport when compared to waiting for reevaluation at the perinatal center. These findings suggest that surfactant can be used safely prior to the interhospital transport of preterm infants, but this treatment does not seem to confer benefit over waiting for reevaluation, and possible surfactant treatment, at the tertiary perinatal center.

[Therapy trends in the prevention of radiation-induced diarrhea after pelvic and abdominal irradiation. Results of a tricenter study]

PURPOSE

Radiotherapy induced diarrhea and convulsive pain are severe side-effects of irradiation of the pelvis and the abdomen leading often to an interruption of the treatment. Up to now these side-effects were only treated symptomatically, prophylactic therapies are not known.

PATIENTS AND METHODS

During the years 1992 and 1993 174 patients who obtained radiotherapy in the pelvis or the abdomen because of different malignancies were observed referring to the diarrhea-prophylactic effect of Smectite (= Skilpin). 80 patients received Smectite at the beginning of radiotherapy, 94 patients of the control group were treated with motility modifying drugs when diarrhea appeared. The following parameters were compared: Frequency, consistence and incontinence of stool, tenesmus and the onset of diarrhea.

RESULTS

67.0% (n = 63) of the patients in the control group developed diarrhea, whereas in the pretreated Smectite-group only 37.5% of the cases (n = 30) developed diarrhea. The first appearance of diarrhea was at day 17 in the pretreated group and averagely at day 11 in the control group. 44% of the patients in the control group suffered from tenesmus versus 25% in the Smectite-group.

CONCLUSION

In comparison to the symptomatic treatment of radiation enteritis the prophylactic application of Smectite is able to reduce the diarrhea from the beginning of radiotherapy or at least to reduce the pathological frequency of stool and therefore to increase the quality of life.

Developing the gastroenterology certification examination

This paper describes a typical procedure for the development of credentialing examinations. Specifically, the paper provides the developmental history of the Certification Examination for Gastroenterology Nurses and Associates. In the course of the paper, a four-step approach to examination development is outlined. The steps include role delineation, item writing, examination construction and passing score determination. All phases of the examination development process are viewed in the light of their contribution to the public protection responsibility of the Certifying Board of Gastroenterology Nurses and Associates.

[Cough associated with captopril and enalapril]

Persistent dry cough is not a known adverse reaction of captopril and enalapril. We present 5 patients with persistent dry cough severe enough to warrant withdrawal of the drug, which resulted in rapid and complete recovery. Challenge with the drugs induced recurrence of cough. The pathogenesis of the reaction is unknown, but possible mediators include bradykinin and prostaglandins.