Hyperfractionated Cyclophosphamide and Dexamethasone Alone or in Combination with Daratumumab and/or Carfilzomib for the Treatment of Relapsed or Refractory Multiple Myeloma: A Single-Center Retrospective Analysis

BACKGROUND

Hyperfractionated cyclophosphamide and dexamethasone (HyperCd) alone, or with carfilzomib(K) and/or daratumumab(D), represents a potential treatment option when rapid disease control is needed for patients with aggressive presentations of relapsed/refractory multiple myeloma (RRMM).

PATIENTS AND METHODS

This is a single-center, retrospective analysis of adult patients with RRMM who received HyperCd with or without K and/or D between May 1, 2016 and August 1, 2019 at the University of Texas MD Anderson Cancer Center. We here report treatment response and safety outcomes.

RESULTS

Data from 97 patients, 12 with plasma cell leukemia (PCL), were reviewed in this analysis. Patients had had a median of 5 prior lines of therapy and received a median of 1 consecutive cycle of hyperCd-based therapy. The overall response rate (ORR) of all patients was 71.8% (HyperCd 75%, HyperCdK 64.3%, D-HyperCd 73.3%, and D-HyperCdK 76.9%). Median progression-free survival and overall survival among all patients was 4.3 months (HyperCd 3.1 months, HyperCdK 4.5 months, D-HyperCd 3.3 months, and D-HyperCdK 6 months) and 9.0 months (HyperCd 7.4 months, HyperCdK 9.0 months, D-HyperCd 7.5 months, and D-HyperCdK 15.2 months), respectively. Grade 3/4 hematologic toxicities were common, thrombocytopenia being the most frequent at 76%. Notably, 29-41% of patients per treatment group had existing grade 3/4 cytopenias at initiation of hyperCd-based therapy.

CONCLUSION

HyperCd-based regimens provided rapid disease control among MM patients, even when heavily pre-treated and with few remaining treatment options. Grade 3/4 hematologic toxicities were frequent, but manageable with aggressive supportive care.

Relationship between coronary artery calcium score and myocardial blood flow reserve in patients with suspected coronary artery disease

Funding Acknowledgements

Type of funding sources: None.

Background

Both the Coronary Artery Calcium Score (CACS), a non-invasive surrogate for atherosclerotic burden, and reduced myocardial blood flow reserve (MBFR) with normal perfusion, a non-invasive surrogate for coronary vasomotor dysfunction, independently predict future cardiovascular events. The relationship between CACS and MBFR, and potential clinical factors affecting it, is not well understood.

Methods

Among 9467 consecutive patients without known history of CAD who had normal perfusion on 82Rb PET-CT and a concomitantly measured CACS between 01/2010 - 06/2020 within our health system, we assessed the relationship between CACS and MBFR. Multiple linear regression was used to predict MBFR using CACS, adjusted for age, sex, BMI, risk factors, symptoms, resting LVEF and vital signs. Interactions of age, sex, diabetes, and symptoms with CACS were assessed to evaluate if they modified the relationship of CACS with MBFR.

Results

Mean age (SD) of the study cohort was 66.4 (12.6) years, 64% were women, 64% had chest pain and 47% had dyspnea. Reduced MBFR (<2) was present in 44% and CAC >0 in 74% of patients.  There was a modest inverse correlation between MBFR and CACS, r= - 0.18, p = < 0.0001 (Figure). In adjusted analyses, CACS (β for CAC per 100 = -0.013 [95% CI: -0.015, -0.010]) was weakly associated with MBFR, and age, sex, diabetes, or symptoms did not modify this relationship (all interaction p-values >0.1). Older age, female sex, presence of hypertension, diabetes, dyspnea, lower LVEF, higher baseline HR and higher CACS independently predicted reduced MBFR, but explained only 20% of the variance in MBFR (R2 =0.20).

Conclusion

There is a weak relationship between CACS and MBFR, which is not modified by age, sex, symptoms, or other CV risk factors. Coronary calcium burden does not completely reflect the overall disease activity within the coronary circulation, and measures of coronary vasomotor function such as MBFR may offer complementary information on CAD risk to that provided by the total burden of calcified atherosclerosis.

Investigation of association between bovine viral diarrhoea virus and cervid herpesvirus type-1, and abortion in New Zealand farmed deer

This study tested for association between bovine viral diarrhoea virus (BVDv) and cervid herpesvirus type-1 (CvHV-1) exposure and abortion in New Zealand farmed red deer. Rising two-year-old (R2, n = 22,130) and mixed-age (MA, n = 36,223) hinds from 87 and 71 herds, respectively, throughout New Zealand were pregnancy tested using ultrasound early in gestation (Scan-1) and 55-89 days later (Scan-2) to detect mid-term abortion. Sera from aborted and non-aborted hinds at Scan-2 were tested for BVDv and CvHV-1 using virus neutralisation tests. Available uteri from aborted hinds and from hinds not rearing a calf to weaning were tested by PCR for herpesvirus DNA. In herds with aborted hinds, 10.3% of 639 R2 and 17.2% of 302 MA hinds were sero-positive for BVDv and 18.6% of 613 R2 and 68.5% of 232 MA hinds were sero-positive for CvHV-1. There was no association between BVDv sero-status and abortion at animal level (R2 p = 0.36, MA p = 0.76) whereas CvHV-1 sero-positivity was negatively associated with abortion in MA hinds (p = 0.01) but not in R2 hinds (p = 0.36), MA). Eleven of 108 uteri from aborted R2 hinds but no MA hinds were positive for herpesvirus DNA. Vaginal samples from four R2 and one MA aborted hinds tested were negative for herpesvirus DNA. A Cervid Rhadinovirus type-2 (CRhV-2) was identified in seven PCR positive uteri samples. Findings suggest that BVDv and CvHV-1 may not be associated with abortion in R2 hinds, but association needs to be tested further in MA hinds. The role of CRhV-2 requires clarification.

Single-step endoscopic ultrasonography-guided drainage of peripancreatic fluid collections with a single self-expandable metal stent and standard linear echoendoscope

Endoscopic ultrasonography (EUS)-guided drainage of peripancreatic fluid collections (PFCs) is a well described alternative to surgery or percutaneous drainage. However, it is limited by the requirement for a large working channel that allows multiple plastic stent placement, which is only commercially available on therapeutic linear echoendoscopes. Herein, we describe the drainage of PFCs with a single self-expandable metal stent (SEMS) using a single-step technique and standard linear echoendoscope. Seven cases were identified during a retrospective chart review, and included all patients who had undergone EUS-guided drainage of PFCs during a 6-month period. The mean age was 46 years (range 25 - 70 years) and all patients were symptomatic. The mean diameter of PFCs was 8 cm (range 4.1 - 12.5 cm). Previous percutaneous drainage had failed in three patients. A total of 10 PFCs were drained. Three patients had two cysts drained by the same stent and one patient had two separate procedures to drain two distinct cysts. The SEMS was in place for a mean of 13 weeks (range 4 - 34 weeks). Successful placement of SEMS was achieved in all seven cases. Patients were followed for a mean of 18 weeks (range 7 - 35 weeks), and symptom improvement was achieved in all cases. Complete resolution of PFC was achieved in 9 /10 cysts. No complications were encountered. Single-step EUS-guided drainage of PFCs using a single 10-mm SEMS and a standard linear echoendoscope appears to be a feasible endoscopic technique with excellent technical and clinical success rates.

Pharmacological screening of Coriandrum sativum Linn. for hepatoprotective activity

Objective:

Coriandrum sativum (Linn.), a glabrous, aromatic, herbaceous annual plant, is well known for its use in jaundice. Essential oil, flavonoids, fatty acids, and sterols have been isolated from different parts of C. sativum. The plant has a very effective antioxidant profile showing 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, lipoxygenase inhibition, phospholipid peroxidation inhibition, iron chelating activity, hydroxyl radical scavenging activity, superoxide dismutation, glutathione reduction and antilipid peroxidation due to its high total phenolic content with the presence of constituents like pyrogallol, caffeic acid, glycitin, etc.

Materials and Methods:

This study was aimed at investigating the hepatoprotective activity of C. sativum against carbon tetrachloride (CCl4), with estimation of serum serum glutamyl oxaloacetic acid transaminase (SGOT), serum glutamyl pyruvate transaminase (SGPT), alkaine phosphatase (ALP) and bilirubin, and with liver histopathology.

Results:

Ethanolic extract was found to be rich in alkaloids, phenolic compounds and flavonoids, and high performance liquid chromatography (HPLC) fingerprinting showed the presence of iso-quercetin and quercetin. C. sativum signifies hepatoprotection by reducing the liver weight, activities of SGOT, SGPT, and ALP, and direct bilirubin of CCl₄ intoxicated animals. Administration of C. sativum extract at 300 mg/kg dose resulted in disappearance of fatty deposit, ballooning degeneration and necrosis, indicating antihepatotoxic activity.

Conclusion:

The results of this study have led to the conclusion that ethanolic extract of C. sativum possesses hepatoprotective activity which may be due to the antioxidant potential of phenolic compounds.

Outcome of patients with metastatic renal cell carcinoma treated with targeted therapy without cytoreductive nephrectomy

BACKGROUND

Cytoreductive nephrectomy (CN) became a standard procedure in metastatic renal cell carcinoma (mRCC) in the immunotherapy era. Historically, median overall survival (OS) of patients treated with interferon alpha (IFN-α) without CN was 7.8 months. Median OS in patients treated with targeted therapy (TT) without CN is unknown.

PATIENTS AND METHODS

We retrospectively reviewed records of patients with mRCC who received TT without CN. Kaplan-Meier methods and Cox regression analysis were used to estimate median OS and identify poor prognostic factors.

RESULTS

One hundred and eighty-eight patients were identified. Most patients had intermediate-risk (54.8%) or poor-risk (44.1%) disease. Median OS for all patients was 10.4 months [95% confidence interval (CI) 8.1-12.5]. By multivariable analysis, elevated baseline lactate dehydrogenase and corrected calcium, performance status of two or more, retroperitoneal nodal metastasis, thrombocytosis, current smoking, two or more metastatic sites, and lymphopenia were independent risk factors for inferior OS. Patients with four or more factors had increased risk of death (hazard ratio 8.83, 95% CI 5.02-15.5, P < 0.001) and 5.5-month median OS. Nineteen patients (10.0%) survived for 2+ years.

CONCLUSIONS

These data highlight the improved OS of patients with mRCC treated with TT without CN, compared with historical IFN-α treatment, and may guide the design of trials investigating the role of CN in the TT era.

The stem cell niche

Virtually every tissue of the adult organism maintains a population of putatively slowly-cycling stem cells that maintain homeostasis of the tissue and respond to injury when challenged. These cells are regulated and supported by the surrounding microenvironment, referred to as the stem cell 'niche'. The niche includes all cellular and non-cellular components that interact in order to control the adult stem cell, and these interactions can often be broken down into one of two major mechanistic categories--physical contact and diffusible factors. The niche has been studied directly and indirectly in a number of adult stem cell systems. Herein, we will first focus on the most well-understood niches supporting the germline stem cells in the lower organisms Caenorhabditis elegans and Drosophila melanogaster before concentrating on the more complex, less well-understood mammalian niches supporting the neural, epidermal, haematopoietic and intestinal stem cells.

Pharmacoeconomic analysis of adjuvant oral capecitabine vs intravenous 5-FU/LV in Dukes' C colon cancer: the X-ACT trial

Oral capecitabine (Xeloda®) is an effective drug with favourable safety in adjuvant and metastatic colorectal cancer. Oxaliplatin-based therapy is becoming standard for Dukes' C colon cancer in patients suitable for combination therapy, but is not yet approved by the UK National Institute for Health and Clinical Excellence (NICE) in the adjuvant setting. Adjuvant capecitabine is at least as effective as 5-fluorouracil/leucovorin (5-FU/LV), with significant superiority in relapse-free survival and a trend towards improved disease-free and overall survival. We assessed the cost-effectiveness of adjuvant capecitabine from payer (UK National Health Service (NHS)) and societal perspectives. We used clinical trial data and published sources to estimate incremental direct and societal costs and gains in quality-adjusted life months (QALMs). Acquisition costs were higher for capecitabine than 5-FU/LV, but higher 5-FU/LV administration costs resulted in 57% lower chemotherapy costs for capecitabine. Capecitabine vs 5-FU/LV-associated adverse events required fewer medications and hospitalisations (cost savings £3653). Societal costs, including patient travel/time costs, were reduced by >75% with capecitabine vs 5-FU/LV (cost savings £1318), with lifetime gain in QALMs of 9 months. Medical resource utilisation is significantly decreased with capecitabine vs 5-FU/LV, with cost savings to the NHS and society. Capecitabine is also projected to increase life expectancy vs 5-FU/LV. Cost savings and better outcomes make capecitabine a preferred adjuvant therapy for Dukes' C colon cancer. This pharmacoeconomic analysis strongly supports replacing 5-FU/LV with capecitabine in the adjuvant treatment of colon cancer in the UK.

Future implications: compliance and failure with antiretroviral treatment

HIV management is currently in an era of effective, potent antiretroviral therapy. Modern drug discovery and development have transformed HIV-1 disease into a treatable, chronic infectious disease. Complete suppression of viral replication is critical for long-term durability of antiretroviral therapy. Partial suppression, even at very low levels, is likely to lead to virologic failure and ultimately to the appearance of drug resistance. The relationship between adherence and resistance to HIV antiretroviral therapy is more complex than to state 'non-adherence increases the risk of drug resistance.' In many patients who fail to respond to initial therapy, the primary reason for failure is their inability to take the prescribed drug regimen or nonadherence.

The economics of treating chronic hepatitis C patients with peginterferon alpha-2a (40 kDa) plus ribavirin presenting with persistently normal aminotransferase

Peginterferon alpha-2a (40 kDa) plus ribavirin is effective at achieving sustained viral response compared with no treatment in patients with chronic hepatitis C (CHC) and persistently normal aminotransferase levels (PNALT). The cost-effectiveness of treating CHC in the setting of PNALT has not been assessed. Disease progression in patients with PNALT was simulated in a Markov model. The rate of fibrosis progression, quality of life and costs for each health state were based on literature estimates. The perspective of the Italian National Health Service was adopted and costs (euro 2003) and benefits were discounted at 3%. Sensitivity analyses were performed on important parameters. The primary analysis compared combination therapy with peginterferon alpha-2a (40 kDa) plus ribavirin to no treatment in a cohort of patients with mean age 45 years, and was based on findings from a multinational, randomized trial in patients with PNALT. In genotype 1 patients, the risk of cirrhosis at 30 years is forecast to fall from 32% with no treatment to 19% with combination therapy, increasing quality-adjusted life years (QALYs) by 0.74 years at an incremental cost per QALY gained of euro 16,831. The 30-year risk of cirrhosis in genotype 2 or 3 is projected to fall to 9% with combination therapy, an increase in QALYs of 1.34 years, at an incremental cost per QALY gained of euro 3,000. Thus treatment of PNALT with peginterferon alpha-2a (40 kDa) plus ribavirin is projected to reduce the incidence of cirrhosis, increase life expectancy and have an acceptable cost-effectiveness ratio from a societal perspective.

Protection of the lip from the activator arm of maxillary distractors

The long spring-loaded distractor arms of maxillary distraction devices can cause pain and ulceration of the upper lip. We describe a simple method to relieve the tension and discomfort on the soft tissues using Silastic tubing.

Cost-effectiveness of combination peginterferon alpha-2a and ribavirin compared with interferon alpha-2b and ribavirin in patients with chronic hepatitis C

BACKGROUND

Sustained virological response (SVR) is the primary objective in the treatment of chronic hepatitis C (CHC). Results from a recent clinical trial of patients with previously untreated CHC demonstrate that the combination of peginterferon alpha-2a and ribavirin produces a greater SVR than interferon alpha-2b and ribavirin combination therapy. However, the cost-effectiveness of peginterferon alpha-2a plus ribavirin in the U.S. setting has not been investigated.

METHODS

A Markov model was developed to investigate cost-effectiveness in patients with CHC using genotype to guide treatment duration. SVR and disease progression parameters were derived from the clinical trials and epidemiologic studies. The impact of treatment on life expectancy and costs were projected for a lifetime. Patients who had an SVR were assumed to remain virus-free for the rest of their lives. In genotype 1 patients, the SVRs were 46% for peginterferon alpha-2a plus ribavirin and 36% for interferon alpha-2b plus ribavirin. In genotype 2/3 patients, the SVRs were 76% for peginterferon alpha-2a plus ribavirin and 61% for interferon alpha-2b plus ribavirin. Quality of life and costs were based on estimates from the literature. All costs were based on published U.S. medical care costs and were adjusted to 2003 U.S. dollars. Costs and benefits beyond the first year were discounted at 3%.

RESULTS

In genotype 1, peginterferon alpha-2a plus ribavirin increases quality-adjusted life expectancy (QALY) by 0.70 yr compared to interferon alpha-2b plus ribavirin, producing a cost-effectiveness ratio of $2,600 per QALY gained. In genotype 2/3 patients, peginterferon alpha-2a plus ribavirin increases QALY by 1.05 yr in comparison to interferon alpha-2b plus ribavirin. Peginterferon alpha-2a combination therapy in patients with HCV genotype 2 or 3 is dominant (more effective and cost saving) compared to interferon alpha-2b plus ribavirin. Results weighted by genotype prevalence (75% genotype 1; 25% genotype 2 or 3) also show that peginterferon alpha-2a plus ribavirin is dominant. Peginterferon alpha-2a and ribavirin remained cost-effective (below $16,500 per QALY gained) under sensitivity analyses on key clinical and cost parameters.

CONCLUSION

Peginterferon alpha-2a in combination with ribavirin with duration of therapy based on genotype, is cost-effective compared with conventional interferon alpha-2b in combination with ribavirin when given to treatment-naïve adults with CHC.

A "round block" purse-string suture in facial reconstruction after operations for skin cancer surgery

Removal of skin cancers in the head and neck region usually results in a circular or oval defect, which must be reconstructed immediately using one of several techniques. Larger defects can present a difficult aesthetic problem. The purse-string suture is particularly suited to such large defects where the skin is lax. We report 51 cases where this technique was used in the head and neck region. All defects were considerably reduced in size and some required a small skin graft to complete the reconstruction. Initially many redundant skin folds and considerable local distortion were seen but these improved with time. The technique is simple, inexpensive, and the results are satisfactory in appropriately selected cases. Comprehensive discussion to prepare patients for the gross initial distortion and the long period of retention of the suture makes the procedure acceptable to patients.

Dental knowledge of accident and emergency senior house officers

OBJECTIVES

To determine the dental knowledge of accident and emergency (A&E) senior house officers (SHOs).

METHOD

A telephone survey of A&E departments in England with more than 30 000 new attendances per year was conducted between November 1998 and July 1999. The questionnaire covered basic dental knowledge as well as scenarios of some common dental problems encountered in the A&E department.

RESULTS

Most SHOs in this study saw between one and five dental problems each week. Of the 102 SHOs in this survey, 52% had no previous training in examination of the mouth. Only 52% knew the approximate date of eruption of a permanent upper central incisor. In the treatment of post-extraction bleeding, 36% knew the first line of treatment. When presented with a scenario of a patient with a dental infection, only 29% gave the optimal empirical treatment.

CONCLUSIONS

There is a need for better dental education among medical personnel. Guidelines or algorithms for the management of some common dental problems would also be useful as well as standard written advice sheets for patients with dental problems.

Abciximab suppresses the rise in levels of circulating inflammatory markers after percutaneous coronary revascularization

BACKGROUND

Previous investigators have shown that systemic markers of inflammation may be increased in patients with acute ischemic syndromes or after percutaneous coronary revascularization and that persistent elevation in these markers is predictive of excess risk of subsequent adverse cardiac events. By virtue of its cross-reactivity with the glycoprotein IIb/IIIa, avbeta3, and alphaMbeta2 receptors, abciximab may reduce inflammatory processes. Methods and Results-- Assays for the inflammatory markers C-reactive protein, interleukin-6, and tumor necrosis factor-alpha were performed on serum samples obtained from 160 patients in a placebo-controlled, randomized trial of abciximab during angioplasty. Eighty patients each had received a placebo or abciximab bolus plus a 12-hour infusion. Serum samples were drawn at baseline (before revascularization), 24 to 48 hours after study drug administration, and 4 weeks after study drug administration. Between baseline and 24 to 48 hours, the increase in C-reactive protein was 32% less in patients receiving abciximab than placebo (P=0.025); the rise in interleukin-6 levels was 76% less in the abciximab group (P<0.001); and the rise in tumor necrosis factor-alpha levels was 100% less with abciximab therapy (P=0.112). By 4 weeks, most marker levels had returned to baseline, with no significant differences between placebo and abciximab groups.

CONCLUSIONS

Systemic markers of inflammation increase in the first 24 to 48 hours after angioplasty, but the magnitude of that rise is diminished by periprocedural abciximab. Some of the long-term clinical benefit derived from this agent may be related to an anti-inflammatory effect.

Innovative approaches to educating medical students for practice in a changing health care environment: the National UME-21 Project

In today's continually changing health care environment, there is serious concern that medical students are not being adequately prepared to provide optimal health care in the system where they will eventually practice. To address this problem, the Health Resources and Services Administration (HRSA) developed a $7.6 million national demonstration project, Undergraduate Medical Education for the 21st Century (UME-21). This project funded 18 U.S. medical schools, both public and private, for a three-year period (1998-2001) to implement innovative educational strategies. To accomplish their goals, the 18 UME-21 schools worked with more than 50 organizations external to the medical school (e.g., managed care organizations, integrated health systems, Area Health Education Centers, community health centers). The authors describe the major curricular changes that have been implemented through the UME-21 project, discuss the challenges that occurred in carrying out those changes, and outline the strategies for evaluating the project. The participating schools have developed curricular changes that focus on the core primary care clinical clerkships, take place in ambulatory settings, include learning objectives and competencies identified as important to providing care in the future health care system, and have faculty development and internal evaluation components. Curricular changes implemented at the 18 schools include having students work directly with managed care organizations, as well as special demonstration projects to teach students the knowledge, skills, and attitudes necessary for successfully managing care. It is already clear that the UME-21 project has catalyzed important curricular changes within 12.5% of U.S. medical schools. The ongoing national evaluation of this project, which will be completed in 2002, will provide further information about the project's impact and effectiveness.

Pressure-flow specificity of inspiratory muscle training

The inspiratory muscles (IM) can be trained by having a subject breathe through inspiratory resistive loads or by use of unloaded hyperpnea. These disparate training protocols are characterized by high inspiratory pressure (force) or high inspiratory flow (velocity), respectively. We tested the hypothesis that the posttraining improvements in IM pressure or flow performance are specific to training protocols in a way that is similar to force-velocity specificity of skeletal muscle training. IM training was accomplished in 15 normal subjects by use of three protocols: high inspiratory pressure-no flow (group A, n = 5), low inspiratory pressure-high flow (group B, n = 5), and intermediate inspiratory pressure and flow (group C, n = 5). A control group (n = 4) did no training. Before and after training, we measured esophageal pressure (Pes) and inspiratory flow (VI) during single maximal inspiratory efforts against a range of external resistances including an occluded airway. Efforts originated below relaxation volume (Vrel), and peak Pes and VI were measured at Vrel. Isovolume maximal Pes-VI plots were constructed to assess maximal inspiratory pressure-flow performance. Group A (pressure training) performed 30 maximal static inspiratory maneuvers at Vrel daily, group B (flow training) performed 30 sets of three maximal inspiratory maneuvers with no added external resistance daily, and group C (intermediate training) performed 30 maximal inspiratory efforts on a midrange external resistance (7 mm ID) daily. Subjects trained 5 days/wk for 6 wk. Data analysis included comparison of posttraining Pes-VI slopes among training groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Sentinel surveillance of HIV infection among new inmates and implications for policies of corrections facilities

Seroprevalence surveys of incoming inmates provide useful sentinel information on human immunodeficiency virus (HIV) infection rates among groups that practice HIV-associated high-risk behaviors. In addition, such data are beneficial to corrections officials in the formulation of institutional policies to prevent HIV infection. Inmates entering the Michigan corrections system from December 1987 to March 1988 participated in blind, anonymous serosurveys for HIV infection. Eight of 802 entering inmates (1.0 percent) were seropositive; most seropositive persons reported intravenous drug use. The most common risk behaviors reported by study participants were intravenous drug use (20.0 percent), multiple sexual partners (37.1 percent), and infrequent (that is, never or seldom) use of condoms (82.6 percent). Women reported the highest rates of intravenous drug use (35.1 percent) and needle-sharing (19.4 percent). Results from this study indicate that in spite of wide-spread HIV-associated risk behaviors, the extent of HIV-seropositivity among incoming inmates in Michigan is relatively low. Such data suggest that there is still time to impact the course of the AIDS epidemic among high-risk groups in States where the prevalence of HIV infection is relatively low. The data also indicate that the potential for HIV spread in correctional facilities is noteworthy and that HIV prevention education and substance abuse treatment services are needed in corrections facilities.

Activation and immortalization of leukaemic B cells by Epstein-Barr virus

We have studied the responses of chronic leukaemic B cells to infection by Epstein-Barr virus (EBV). Our results define one population of B lymphocytes, represented by prolymphocytic leukaemic (PLL) cells, which are highly susceptible to immortalization by EBV. Another B-cell type, represented by chronic lymphocytic leukaemic (CLL) cells, can be readily infected by the virus but is resistant to immortalization. Comparative studies of viral and cellular related events early after infection in these 2 cell types reveal that both express the EB viral nuclear antigen (EBNA) complex, but the immortalization-resistant CLL cells fail to express the latent membrane protein (LMP), which can be detected in PLL cells 48 hr after infection. Circularization of the linear viral genome could be detected at 7 days post infection in the PLL cells, but only in 2 out of 4 CLL cells tested. Both CLL and PLL cells show increased surface expression of CD23 and HLA-DR molecules after infection but, whereas PLL cells show an increase in size, together with RNA and DNA synthesis indicative of cell cycle progression, CLL cells appear to be arrested in the G1/S phase of the cycle. The results suggest that the outcome of infection by EBV is determined by the nature of the target cell rather than by random virus-related events. The correlation between the block in immortalization of CLL cells and their failure to express LMP suggests that expression of this protein is essential for in vitro immortalization of B cells. The failure to detect circularization in some EBV-infected CLL cells suggests that this, as well as LMP expression, may be dependent on prior activation of the B cell by EBV, an event which may vary between the different CLL samples tested.

Conjoint twins (1)

Two cases of Conjoined twins are reported. The etiology, incidence, diagnosis and management are discussed. It is suggested that if conjoined twins are diagnosed before labour, of if there is dystocia, Caesarean section is the treatment of choice.

Heterogeneity among strains of Mycoplasmatales virus-laidlawii 2

Five isolates of Mycoplasmatales virus-laidlawii 2 (MV-L2) derived from bovine strains of Acholeplasma laidlawii were shown to differ in host range, plaque morphology and neutralization tests with MV-L2 antiserum. Cross-testing using virus resistant clones of A. laidlawii confirmed the heterogeneity of this group. Adaptation of viruses to sub-optimal host was demonstrated.

Effect of pH on metabolism and ultrastructure of guinea pig cerebral cortex slices

Lactic acidosis is a prominent biochemical alteration which follows cerebral ischemia and is of sufficient degree to result in pH decrease in involved and adjacent tissue. Because of the significance of acidosis in the cerebral ischemic process, we have investigated ultrastruclural changes and some biochemical parameters under varying pH conditions using guinea pig cerebral cortex slices.

Metabolic rates decreased markedly during acidic incubations, and increased only minimally during basic incubations. Acidic pH affected oxygen and glucose utilization rates and fine structure to a greater degree than did an equal change in pH from 7.4 toward the alkaline. Glucose consumption was affected by pH deviations from 7.4 to a greater degree than oxygen uptake.