The nature of after-hours telephone medical practice by GI fellows.

OBJECTIVE: Gastroenterology fellows on-call often serve as the initial or only contact for patients calling "after hours" with questions and symptoms. These fellows are rarely trained specifically in how to handle these calls. The aim of this study was to determine whether there are particular topics in telephone medicine that ought to be covered in new fellow training. Therefore, we sought to evaluate the nature of after-hours pages initiated by patients and to document the advice given by fellows. METHODS: The content of 100 patient-initiated telephone calls with GI fellows was recorded prospectively over 7 months. We included pages received between 5 PM and 8 AM daily as well as daytime calls on weekends. Fellows documented the time and length of the call, the issue raised by the patient, the advice given, and the patient's gender and attending gastroenterologist. When a particular patient paged more than once in a 24-h period, the repeat calls were not counted toward the 100-call tally. RESULTS: Twenty-two percent of calls occurred between 11 PM and 7 AM. Eighty-three percent of calls lasted less than 10 min. Sixty-seven percent of patients called because of symptoms. Only 30% of patients calling with symptoms were referred to the emergency room. Although only 1 of 13 patients with procedure-related (i.e., postendoscopy) symptoms required admission to the hospital, 18 of 54 (33%) patients with nonprocedure-related symptoms required admission either immediately or within a month of calling after hours. CONCLUSIONS: Most after-hours calls from patients are related to symptoms. Patients calling with postprocedure symptoms rarely require admission to the hospital. Conversely, a significant number of patients calling with non-procedure-related symptoms require admission within 30 days. Fellowship directors should consider providing training to fellows in the evaluation of symptoms over the telephone.

Does mortality occur early or late in acute pancreatitis?

UNLABELLED: Several prior studies have suggested that 80% of deaths in acute pancreatitis occur late as a result of pan-creatic infection. Others have suggested that approx half of deaths occur early as a result of multisystem organ failure. The aim of the present study was to determine the timing of mortality of acute pancreatitis at a large tertiary-care hospital in the United States. METHODS: Patients with a diagnosis of acute pancreatitis (ICD-9 code 577.0) admitted to Brigham and Women's Hospital from October 1, 1982 to June 30, 1995 were retrospectively studied to determine total mortality, frequency of early vs late deaths, and clinical features of patients with early (< or = 14 d after admission) or late deaths (> 14 d after admission). RESULTS: The overall mortality of acute pancreatitis was 2.1% (17 deaths among 805 patients). Eight deaths (47%) occurred within the first 14 d of hospitalization (median d 8, range 1-11 d), whereas 9 occurred after 14 d (median d 56, range 19-81). Early deaths resulted primarily from organ failure. Late deaths occurred postoperatively in 8 patients with infected or sterile necrosis and 1 patient with infected necrosis treated medically. CONCLUSION: Approximately half of deaths in acute pancreatitis occur within the first 14 d owing to organ failure and the remainder of deaths occur later because of complications associated with necrotizing pancreatitis. Improvement in mortality in the future will require innovative approaches to counteract early organ failure and late complications of necrotizing pancreatitis.

Optical coherence tomography: advanced technology for the endoscopic imaging of Barrett's esophagus.

BACKGROUND AND STUDY AIMS: Endoscopic optical coherence tomography (OCT) is an emerging medical technology capable of generating high-resolution cross-sectional imaging of tissue microstructure in situ and in real time. We assess the use and feasibility of OCT for real-time screening and diagnosis of Barrett's esophagus, and also review state-of-the-art OCT technology for endoscopic imaging. MATERIALS AND METHODS: OCT imaging was performed as an adjunct to endoscopic imaging of the human esophagus. Real-time OCT (13-microm resolution) was used to perform image-guided evaluation of normal esophagus and Barrett's esophagus. Beam delivery was accomplished with a 1-mm diameter OCT catheter-probe that can be introduced into the accessory channel of a standard endoscope. Different catheter-probe imaging designs which performed linear and radial scanning were assessed. Novel ultrahigh-resolution (1.1-microm resolution) and spectroscopic OCT techniques were used to image in vitro specimens of Barrett's esophagus. RESULTS: Endoscopic OCT images revealed distinct layers of normal human esophagus extending from the epithelium to the muscularis propria. In contrast, the presence of gland- and crypt-like morphologies and the absence of layered structures were observed in Barrett's esophagus. All OCT images showed strong correlations with architectural morphology in histological findings. Ultrahigh-resolution OCT techniques achieved 1.1-microm image resolution in in vitro specimens and showed enhanced resolution of architectural features. Spectroscopic OCT identified localized regions of wavelength-dependent optical scattering, enhancing the differentiation of Barrett's esophagus. CONCLUSIONS: OCT technology with compact fiberoptic imaging probes can be used as an adjunct to endoscopy for real-time image-guided evaluation of Barrett's esophagus. Linear and radial scan patterns have different advantages and limitations depending upon the application. Ultrahigh-resolution and spectroscopic OCT techniques improve structural tissue recognition and suggest future potential for resolution and contrast enhancements in clinical studies. A new balloon catheter-probe delivery device is proposed for systematic imaging and screening of the esophagus.

Characterisation of Leishmania isolates from Laikipia District, Kenya.

Using cloned kDNA sequences from the reference strain of Leishmania tropica IC-067, we have screened leishmanial isolates from Laikipia District of Kenya and identified these isolates as L. tropica. One isolate, IC-331, from a rat (Rattus rattus) was typed as L. tropica. This is the first time that L. tropica has been isolated from a wild rodent in Kenya and thus the first indication that the disease caused by L. tropica might be a zoonosis. The leishmanial isolates, especially those of sandflies, display extensive heterogeneity, prompting a need for selecting local and/or regional reference strains to generate species-specific DNA probes for use in identifying field isolates.

Race, family history of hypertension, and sympathetic response to cold pressor testing.

This laboratory recently reported that the blood pressure and muscle sympathetic nerve activity (MSNA) responses to cold pressor testing are greater in normotensive blacks than in age- and weight-matched normotensive whites. The present study was designed to determine the relationship between race, family history of hypertension, and sympathetic response to cold pressor testing. The study used microneurography to measure MSNA responses to cold pressor testing in normotensive blacks with (n = 8) and without (n = 8) and normotensive white subjects with (n = 8) and without (n = 10) a positive family history of hypertension. Resting blood pressure was lower in black subjects without a positive family history of hypertension but otherwise resting blood pressure, heart rate, and MSNA were similar in the four groups. Black subjects with a family history of hypertension manifested a greater increase in blood pressure and MSNA than both white groups. Blood pressure and sympathetic responses of black subjects with a negative family history of hypertension tended to be intermediate and were not statistically different from the other three groups. These results indicate that the greater sympathetic response to cold stress observed in normotensive African-Americans is true only of black subjects with a positive family history of hypertension.

Studies on the vectors of leishmaniasis in Kenya: phlebotomine sandflies of Sandai location, Baringo district.

Adults of phlebotomine sandflies were collected from natural and man-made habitats in Sandai area of Baringo district using sticky and CDC light traps. Three sandfly species belongings to the Phlebotomus genus and eight species belonging to the Sergentomyia genus were recorded in the area. These flies fall into "perennial" group as they appeared to breed throughout the year. During the dry season there was an increase of sandfly densities in animal burrows and termite mounds, the main sandfly breeding places. Tree holes and human habitations constituted the major sandfly resting places during the wet season. Sandflies of the Phlebotomus genus were more collected in termite mounds and inside houses using CDC light traps, whereas in animal burrows they were more collected by sticky traps than by CDC traps. Sandflies of the Sergentomyia genus were equally collected by sticky traps and CDC light traps. However, in animal burrows and in human habitations, sandflies were more collected by CDC light traps than by sticky traps. On statistical analysis, CDC light traps seemed to be effective inside houses and in animal burrows. In termite mounds both traps yielded uniform results.

Effects of permethrin-treated screens on phlebotomine sand flies, with reference to Phlebotomus martini (Diptera: Psychodidae).

Effects of permethrin-treated screens on the sand fly, Phlebotomus martini Parrot, a vector of visceral leishmaniasis in Kenya, were evaluated after the eighth treatment. Screens treated with 0.50 g/m2 of permethrin 20% emulsifiable concentrate were fitted inside houses and re-treated every 6 mo from August 1989 to December 1993. Before application of the treated screens, a geometric mean of 0.83 P. martini were collected per trap night inside houses, whereas after the eighth treatment only 0.05 sand flies were caught. P. martini abundance was reduced by 88.8%. Analysis of the effects of treated screens on the total sand fly population (all species) indicated that 1.79 sand flies were collected per night per house before deployment of treated screens, whereas 0.16 flies were caught after the eighth treatment. The percentage of sand fly reduction inside treated houses increased with successive treatment of the screens, and a reduction of 81.4% was observed after the eighth treatment. Permethrin-treated screens did not reduce the sand fly engorgement rate inside houses.

Choice of resting sites by Anopheles gambiae (Diptera: Culici) in Mwea Rice Irrigation Scheme, Kirinyaga District, Kenya.

Investigations on Anopheles gambiae were carried out in Mwea Rice Irrigation Scheme, Kenya, to determine their preference for resting on various colours of fabrics and bare walls inside rural houses. The inside wall surface of each house was divided into upper, middle and lower sections and the section further partitioned into subsections measuring 0.6 x 0.3m. Two sets of experiments were conducted: one in which the walls were partly fitted with one colour of fabric at a time (double-choice situation), while in the other the walls were fitted with a combination of six colours (red, black, yellow, white, green and blue) of fabric at once, (multiple-choice situation). The number of mosquitoes resting on each of the pieces of cloth pinned to the walls and the uncovered subsections of the wall were recorded for each section of the wall after 24 hours. The results showed resting preference for cloth covered parts of the walls. The white colour was found to best attract mosquitoes followed by colours red, yellow, black, blue and green. The hanging strips in the middle of the houses had fewer mosquitoes resting on them than those on the wall.

Ecology of Sergentomyia garnhami, (Diptera:Psychodidae) in a kala-azar endemic area of Tseikuru, Kitui District, Kenya. I: The breeding sites.

The breeding sites of S. garnhami and other phlebotomine sandflies were investigated from February 1989-June 1990. Sandflies were recovered from 15 out of the 17 ecological habitats studied while S. garnhami was recovered from fourteen. Termite hills were the most preferred breeding sites for most phlebotomine sandflies but it was not possible to identify the preferred breeding sites of S. garnhami as all the sites yielded only one to three flies. S. garnhami were recovered from soil samples from both inside and outside human homes as well as from sylvatic sites. Daily pattern of emergence of sandflies showed that 60 days were sufficient for most sandflies to emerge while at least 100 days were required for S. garnhami.

Ecology of Sergentomyia garnhami, (Diptera:Psychodidae) in a kala-azar endemic area of Tseikuru, Kitui District, Kenya. II: Day resting sites.

A search for the day resting sites of S. garnhami and other phlebotomine sandflies in ten ecological habitats in Tseikuru area of Kitui District, Kenya, was carried out between November and December 1990. S. garnhami was collected in nine out of ten sites investigated, suggesting a wide distribution of the resting sites. S. garnhami constituted 23.4% of the total collections with termite hills being the most preferred site. Weekly trapping records showed that S. garnhami appeared in the field three weeks after the first rains of the season.

Host blood meals and chromosomal inversion polymorphism in Anopheles arabiensis in the Baringo District of Kenya.

Studies were carried out in the villages of Kapkuikui and Maji-Ndege in the Loboi area of Baringo District, Kenya, to obtain baseline data on species identification of the Anopheles gambiae group, their feeding and resting behavior, and their frequencies of chromosomal inversions. This was carried out towards predicting the effect of introducing permethrin-impregnated cloths or other intervention measures. In this study, Anopheles arabiensis was identified as the only species of the An. gambiae group. This species contained 2 inversions, 2Rb and 3Ra, occurring at frequencies ranging from 55 to 60%, and from 5 to 11%, respectively. There was no evidence for nonrandom mating. Indoor- and outdoor-collected samples were significantly different in respect of inversion 3Ra in one village and in the distribution of the different sources of blood meals in both areas. In these villages, 37% of indoor-resting mosquitoes fed outside before entering houses to rest.

Muscle sympathetic nervous system activity in black and Caucasian hypertensive subjects.

OBJECTIVE: To compare muscle sympathetic nerve activity (MSNA) in age- and weight-matched African-Americans and American Caucasians with primary hypertension. DESIGN: Using microneurography, we compared MSNA at rest and in response to cold-pressor testing and handgrip exercise in 13 hypertensive African-Americans and 12 hypertensive American Caucasians. METHODS: All subjects were withdrawn from antihypertensive medications for at least 2 weeks before the study. MSNA was recorded from the left peroneal nerve. RESULTS: Resting MSNA was similar in the Blacks and the Caucasians. Increases in muscle efferent activity, mean arterial pressure and heart rate in response to the cold pressure and handgrip exercise were not significantly different in Black and in Caucasian subjects. CONCLUSION: MSNA, either at rest or in response to certain laboratory stressors, is not different in Black and in Caucasian hypertensive subjects with similar resting blood pressures.

Cutaneous leishmaniasis in Kenya: Sergentomyia garnhami (Diptera Psychodidae), a possible vector of Leishmania major in Kitui District: a new focus of the disease.

Investigations on phlebotomine sandflies in Tseikuru, Kitui District, Kenya were carried out to determine the vectors of Leishmania major. Sandflies were trapped from animal burrows over a period of one year using castor oil-smeared sticky traps. Nineteen phlebotomine sandfly species were identified and their prevalence in this habitat determined. Dissections on the parous sandflies resulted in the isolation of Leishmania parasites from Phlebotomus martini and Sergentomyia garnhami. The isolated parasites were cultured in NNN medium and were consequently mass cultured in RPMI medium for biochemical characterisation. The parasites from S. garnhami were typed as Leishmania major.

Normotensive blacks have heightened sympathetic response to cold pressor test.

The purpose of this study was to compare sympathetic nerve activity responses to the cold pressor test in black and white normotensive subjects. We recorded muscle sympathetic nerve activity (microneurography of the peroneal nerve), arterial blood pressure, and heart rate in 9 normotensive American blacks (24 +/- 2 years, mean +/- SEM) and 10 normotensive American whites (28 +/- 2 years) at rest and during hand immersion in ice water (cold pressor test). Body weight was not different in the two groups (72.4 +/- 3.7 versus 74.1 +/- 3.8 kg, black versus white subjects). During supine rest, mean arterial pressure (92 +/- 2 versus 93 +/- 3 mm Hg, black versus white), heart rate (66 +/- 4 versus 62 +/- 3 beats per minute, black versus white), and muscle sympathetic nerve burst frequency (12 +/- 2 versus 17 +/- 3 bursts per minute, black versus white) were not different in the two groups. During the cold pressor test, mean arterial pressure, heart rate, and muscle sympathetic nerve activity increased from supine rest in both groups. The magnitudes of increases in mean arterial pressure and total minute muscle sympathetic nerve activity were significantly greater in blacks than whites (33.5 +/- 3 versus 22.4 +/- 3 mm Hg and 416 +/- 24% versus 243 +/- 31% of control, respectively, black versus white, P < .05). The increases in heart rate were most significantly different for the two groups. These data suggest that the enhanced pressor response to cold stress observed in normotensive blacks is attributable to greater increases in peripheral sympathetic nerve activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Malaria prevalence and morbidity in relation to the use of permethrin-treated wall cloths in Kenya.

The effect of permethrin-treated wall cloths (Mbu cloth) on malaria parasitaemia prevalences and malaria morbidity, was evaluated in a population of over 10,000 for a period of three years in the Marigat area, Baringo District, Kenya. The use of the treated cloth in 2,000 houses resulted in significantly lower rates of malaria parasite prevalences with an overall reduction rate of 73% (P < 0.001) in the treated area. Control areas had an initial increase in rate of malaria parasite prevalence of 30% and later a reduction of 31%. There was a slight reduction in spleen rates in the control and treated areas but it was not significant for either between the surveys or among the villages.

PIP: The use of pyrethroid-treated fabrics against disease vectors is a well-accepted vector control strategy worldwide. Most studies have assessed the merits of using impregnated bednets, but this prevention strategy is inappropriate for many households in many communities due to incompatible cultural norms, high cost, the lack of conventional western style beds, sleeping arrangements which differ between cultures, and differences between housing construction styles in rural communities. The International Center of Insect Physiology and Ecology recently developed a technology using cotton wall cloth, Mbu cloth, to control vectors of malaria and leishmaniasis in rural communities in Kenya. Other fabrics such as polyester have even improved the technology by making the cloth lighter and cheaper. The authors evaluated the effect of permethrin-treated Mbu cloth on malaria parasitemia prevalences and malaria morbidity in a population of over 10,000 for a period of 3 years in the Marigat area of Baringo District, Kenya. 2000 houses were fitted with the cloth. The prevalence of malaria parasites was reduced an overall 73% in the treated area. Control areas saw a 30% initial increase in the rate of malaria parasite prevalence followed by a reduction of 31%. Slight reductions in spleen rates were also observed in the control and treated areas, but were insignificant between the surveys and among the villages.

Effect of rice husbandry on mosquito breeding at Mwea Rice Irrigation Scheme with reference to biocontrol strategies.

A study was carried out at Mwea Rice Irrigation Scheme, Kenya, to assess the impact of rice husbandry on mosquito breeding and identify indigenous biocontrol agents with potential for controlling mosquito breeding in the scheme. The study established a close relationship between the schedule of the farming practices (particularly the flooding phase) and mosquito breeding. Two groups of agents, entomopathogenic bacteria (Bacillus thuringiensis var. israelensis) and larvivorous fish, were identified. Laboratory evaluation of the agents produced encouraging results. The bacterial isolates showed broad-spectrum larvicidal potency against Anopheles, Culex and Aedes mosquito larvae and 2 of the fish species, Tilapia zilli and Oreochromis niloticus, demonstrated a strong predation for a mosquito larval diet. To facilitate their use in effective biocontrol strategies, the agents would require further evaluation under field conditions.

Defecation by Anopheles arabiensis mosquitoes of host blood infected with live Trypanosoma congolense.

Female Anopheles arabiensis mosquitoes were experimentally fed on hamsters and BALB/c mice which were either clean or infected with Trypanosoma congolense. The mosquitoes readily fed on either animal. A blood repletion rate of 82.7% was recorded for mosquitoes feeding on hamsters. Seventy seven per cent of the replete mosquitoes continued to feed while at the same time defecating the host's blood in droplets, ejected in quick succession from the anus. Ninety five per cent of mosquitoes defecating blood while feeding on mice infected with T. congolense ejected live parasites along with the blood. Clean mice inoculated intraperitoneally with T. congolense via tail or defecated blood developed parasitaemia between the third and seventh day. This phenomenon could imply possible mechanical transmission of the parasites to the hosts being fed on by the mosquitoes.