Deep vein thrombosis: significant limitations of noninvasive tests

Impedance plethysmography (IPG) has a reputed sensitivity of 95% in the detection of proximal, clinically significant deep venous thrombosis (DVT). A review of the radiologic studies of 100 consecutive patients who underwent both venography and IPG showed venographic evidence of proximal DVT in 40 patients. The IPG was negative in 15 (38%) of these 40 cases. The specificity of the IPG was 83%. The predictive value of a negative study, with this 40% prevalence of DVT, was 77%. These disturbing results indicate a continuing role for venography in the workup of DVT.     

Modelling the force of infection for hepatitis B and hepatitis C in injecting drug users in England and Wales

Background  

Injecting drug use is a key risk factor, for several infections of public health importance, especially hepatitis B (HBV) and hepatitis C (HCV). In England and Wales, where less than 1% of the population are likely to be injecting drug users (IDUs), approximately 38% of laboratory reports of HBV, and 95% of HCV reports are attributed to injecting drug use.     

Health care services utilization stratified by virological and immunological markers of HIV: evidence from a universal health care setting

Objective

The aim of the study was to determine rates of utilization of in‐patient, out‐patient and laboratory services stratified by virological and immunological markers of HIV disease among patients on antiretroviral treatment in British Columbia, Canada.

Methods

We estimated resource utilization for in‐patient visits, out‐patient visits, and laboratory tests among patients initiating antiretroviral treatment between 1 April 1994 and 31 December 2000, with follow‐up to 31 March 2001. Resource use was stratified by CD4 cell count and plasma HIV viral load (pVL) at the time of utilization and rates per 100 patient‐years were calculated for each health care resource.

Results

A total of 2718 patients were included in our analyses. The overall rates of in‐patient visits, out‐patient visits, and laboratory tests were 902, 3001 and 840 per 100 patient‐years, respectively. Utilization was higher for patients with low CD4 cell counts and high pVLs when compared with patients with high CD4 cell counts and low pVLs.

Conclusions

Patients with low CD4 cell counts and high pVLs had the highest use of health care services. Regular follow‐up with health care providers in an out‐patient setting, allowing for proper monitoring and maintenance of HIV care, is important in minimizing unnecessary and potentially costly in‐patient care.     

Mortality is influenced by locality in a major HIV/AIDS epidemic

Objectives

The aim of the study was to compare the risks of death among HIV‐infected patients on highly active antiretroviral therapy (HAART) in two proximate, yet distinct neighbourhoods: a neighbourhood with a high concentration of gay men, and a neighbourhood with a high concentration of injecting drug users.

Methods

We compared the clinical and socioeconomic characteristics of HIV‐infected patients from the two neighbourhoods entering the British Columbia Centre for Excellence in HIV/AIDS Drug Treatment Program from 1 September 1997 to 30 November 2005, using contingency table statistics. Cox survival models and Kaplan–Meier methods were used to estimate the cumulative mortality rates. Results We found significant differences between patients from the two neighbourhoods for all socioeconomic variables. Patients in the neighbourhood with a high concentration of injecting drug users were more likely to be female, have a history of injecting drug use, have a less HIV‐experienced physician and be less adherent. Patients in the neighbourhood with a high concentration of gay men were more likely to have AIDS. Mortality was significantly higher for patients in the neighbourhood with a high concentration of injecting drug users [hazard ratio (HR) 3.01; 95% confidence interval (CI) 1.73, 5.24].

Conclusions

A threefold increase was observed in the risk of death among HIV‐infected individuals on HAART in the neighbourhood with a high concentration of injecting drug users relative to the neighbourhood with a high concentration of gay men. The implications of this study should be assessed in similar HIV/AIDS epicentres.     

Late luteal rescue in the baboon (Papio cynocephalus)

Numerous studies have used human chorionic gonadotrophin (HCG)administration to study the response of the primate ovary togonadotrophin stimulation. These studies are generally performedin the luteal phase with very few studies of the follicularphase. We have studied the effect of both HCG and gonadotrophinreleasing hormone (GnRH) agonist administered at the early follicularphase in normally cycling baboons (Papio cynocephalus). Fivebaboons were treated with increasing doses of HCG for 5 consecutivedays starting on day 1 of the cycle and three untreated baboonsserved as controls. Follicular and luteal phase lengths weredetermined and serum samples were assayed for progesterone,oestradiol and 17-OH progesterone. In a separate study, sixbaboons were treated with GnRH agonist (WY-40972) on days 2-6of the cycle and saline-treated baboons served as controls (n= 5). Mean peak progesterone concentrations (± SE) duringthe treatment interval were 3.88 ± 0.56 ng/ml in HCG-treatedbaboons compared to 0.19 ± 0.07 ng/ml in controls (P<0.001). A similar significant increase (P <0.001) inserum 17-OH progesterone concentrations was also observed (6.13± 1.12 ng/ml versus 1.13 ± 0.49 ng/ml). In associationwith the increase in luteal steroids there was also a significantprolongation of menstrual cycle length from 32.7 ± 1.2days in controls to 46.8 ± 4.9 days in HCG-treated baboons(P <0.05), which involved prolongation of the follicularphase (16.7 ± 1.2 days to 29.0 ± 4.6 days, P <0.05)with no difference in luteal phase length or progesterone concentrations.In GnRH agonist-treated baboons, mean (± SE) cycle lengthwas prolonged to 46.3 ± 1.6 days and in saline-treatedcontrols was 32.8 ± 0.8 days (P <0.001), again thiswas completely represented by the change in follicular phaselength, from 13.4 ± 0.7 days in controls to 27.2 ±2.1 days in agonist-treated baboons (P <0.001). In contrast,there was no significant difference in luteal phase length betweenthese two groups (19.4 ± 0.7 versus 19.2 ± 1.0days). The prolongation of the follicular phase was accompaniedby significant increases in both progesterone (P <0.01) andoestradiol (P <0.01) during GnRH agonist treatment abovecontrol concentrations. Luteal phase concentrations of thesehormones were not different from controls. These results demonstratethe previously unreported finding that gonadotropin stimulationwill rescue the corpus luteum in the next follicular phase.     

Ring sequestrum: radiographic characteristics of skeletal fixation pin- tract osteomyelitis

Major pin-tract infections are a potentially dangerous complication associated with the use of skeletal transfixation pins. The presence of a characteristic radiographic finding, the ring sequestrum, is virtually diagnostic of this abnormality. The clinical and radiographic findings in seven patients treated for this complication are presented. Thermal necrosis without infection presents as a zone of sclerosis around the tract. A narrow, radiolucent halo may surround the dense bone. When a narrow ring sequestrum is surrounded by a radiolucent halo, there is associated infection.     

Splenic syndrome due to sickle cell trait amongst Indian soldiers serving in Kashmir

Background: Heterozygous transmission of gene for Haemoglobin S leads to sickle cell trait. Mostly the trait remains silent with no additional morbidity or mortality. When these persons migrate to higher altitudes, in times of high oxygen demand, some of them develop splenic infarction. This is a rare phenomenon and only 47 such cases had been reported till 2005.     

In vivo layer visualization of rat olfactory bulb by a swept source optical coherence tomography and its confirmation through electrocoagulation and anatomy

Here, we report in vivo 3-D visualization of the layered organization of a rat olfactory bulb (OB) by a swept source optical coherence tomography (SS-OCT). The SS-OCT operates at a wavelength of 1334 nm with respective theoretical depth and lateral resolutions of 6.7 μm and 15.4 μm in air and hence it is possible to get a 3D structural map of OB in vivo at the micron level resolution with millimeter-scale imaging depth. Up until now, with methods such as MRI, confocal microscopy, OB depth structure in vivo had not been clearly visualized as these do not satisfy the criterion of simultaneously providing micron-scale spatial resolution and imaging up to a few millimeter in depth. In order to confirm the OB's layered organization revealed by SS-OCT, we introduced the technique of electrocoagulation to make landmarks across the layered structure. To our knowledge this is such a first study that combines electrocoagulation and OCT in vivo of rat OB. Our results confirmed the layered organization of OB, and moreover the layers were clearly identified by electrocoagulation landmarks both in the OCT structural and anatomical slice images. We expect such a combined study is beneficial for both OCT and neuroscience fields.