Red blood cell size is important for adherence of blood platelets to artery subendothelium

The hematocrit is one of the main factors influencing platelet adherence to the vessel wall. Raising the hematocrit causes an increase of platelet accumulation of about an order of magnitude. Our studies concern the role of red cell size. We have studied this effect using an annular perfusion chamber, according to Baumgartner, with human umbilical arteries and a steady-flow system. Normal human red blood cells (MCV 95 cu mu) increased platelet adherence sevenfold, as the hematocrit increases from 0 to 0.6. Small erythrocytes from goats (MCV 25 cu mu) caused no increment in adherence in the same hematocrit range. Rabbit erythrocytes (MCV 70 cu mu) caused an intermediate increase in adherence. Red blood cells from newborns (MCV 110-130 cu mu) caused a larger increase in platelet adherence than normal red cells at hematocrit 0.4. These results were further confirmed with large red blood cells from two patients. Experiments with small red cells (MCV 70 cu mu) of patients with iron deficiency showed that platelet adherence was similar to normal red cells, provided the red cell diameter was normal. Small red blood cells of a patient with sideroblastic anemia caused decreased adherence. These data indicate that red cell size is of major importance for platelet adherence. Red cell diameter is more important than average volume. However, for size differences in the human range, the hematocrit remains the dominant parameter.     

Durability of giant hiatus hernia repair in 455 patients over 20 years

Introduction

The surgical management of symptomatic giant hiatus hernia (GHH) aims to improve quality of life (QoL) and reduce the risk of life threatening complications. Previous reports are predominantly those with small sample sizes and short follow-up periods. The present study sought to assess a large cohort of patients for recurrence and QoL over a longer time period.

Methods

This was a follow-up study of a prospectively collected database of 455 consecutive patients. Primary repair of GHH was evaluated by endoscopy/barium meal for recurrence and a standardised symptom questionnaire for QoL. Recurrence was assessed for size, elapsed time, oesophagitis and symptoms.

Results

Objective and subjective review was achieved in 91.9% and 68.6% of patients. The median age was 69 years (range: 15–93 years) and 64% were female. Laparoscopic repair was completed in 95% (mesh in 6% and Collis gastroplasty in 7%). The 30-day mortality rate was 0.9%. The proportion of patients alive at five and ten years were 90% and 75% respectively. Postoperative QoL scores improved from a mean of 95 to 111 (p<0.01) and were stable over time (112 at 10 years).The overall recurrence rate was 35.6% (149/418) at 42 months; this was 11.5% (48/418) for hernias >2cm and 24.2% (101/418) for <2cm. The rate of new recurrence at 0–1 years was 13.7% (>2cm = 3.4%, <2cm = 10.3%), at 1–5 years it was 30.8% (>2cm = 9.5%, <2cm = 21.3%), at 5–10 years it was 40.1% (>2cm = 13.8%, <2cm = 26.3%) and at over 10 years it was 50.0% (>2cm = 25.0%, <2cm = 25.0%). Recurrence was associated with oesophagitis but not decreased QoL. Revision surgery was required in 4.8% of cases (14.8% with recurrence). There were no interval major GHH complications.

Conclusions

Surgery has provided sustained QoL improvements irrespective of recurrence. Recurrence occurred progressively over ten years and may predispose to oesophagitis.     

Prospective evaluation of the clinical usefulness of an antigen- specific assay (MAIPA) in idiopathic thrombocytopenic purpura and other immune thrombocytopenias

The diagnosis of idiopathic immune thrombocytopenia remains a clinical diagnosis based on the exclusion of other causes of immune and nonimmune thrombocytopenia. Measurement of platelet-associated Ig (PAIg), while sensitive, is nonspecific for the diagnosis of immune thrombocytopenia. Published experience of antigen capture assays (including monoclonal antibody immobilization of platelet antigens or MAIPA) suggest a high sensitivity and specificity (70% to 80%) in selected groups of patients. In a prospective evaluation of 158 patients with thrombocytopenia from all causes, we report a sensitivity of 51% and specificity of 80% for direct MAIPA assays. MAIPA was considerably better in discriminating immune from nonimmune thrombocytopenia than two assays of PAIgG. Antiplatelet antibodies detected by MAIPA were more frequently directed against the glycoprotein (GP) IIb/IIIa than the GP Ib/IX complex. Our experience suggests that MAIPA assays are useful in the laboratory assessment of thrombocytopenia, should be performed before therapy, and that some patients with 'nonimmune' thrombocytopenia may have genuine antiplatelet antibodies.     

A comparison of objective measures of sexual arousal and interest: visual reaction time and penile plethysmography

This study assessed the reliability and validity of a visual reaction time (VRT) measure of sexual interest (G. G. Abel, J. Huffman, B. Warberg, & C. L. Holland, 1998) and the penile plethysmograph (PPG) with audio stimuli. A sample of 57 sex offenders incarcerated at a high-security military prison completed physiological and self-report measures of sexual interest, including the VRT and the PPG. Results indicated adequate internal consistency for both measures. Convergent validity and an assessment of clinical usefulness for both measures indicated that (a) both measures accurately identified offenders against young boys; (b) the VRT, but not the PPG, significantly identified offenders against adolescent girls; (c) neither measure reached statistical significance in identifying offenders against adult women; and (d) the VRT did not reach statistical significance in identifying offenders against young girls and the PPG did reach statistical significance but in the opposite direction as was expected (i.e., men with female child victims had significantly lower arousal to female child stimuli than did men in other victim choice categories).     

Novel Factors to Improve Prediction of Nodal Positivity in Patients with Clinical T1/T2 Breast Cancers

Background

Memorial Sloan Kettering Cancer Center (MSKCC) and MD Anderson Cancer Center (MDACC) have established nomograms to predict sentinel node positivity. We propose the addition of two novel variables—distance of tumor from the nipple and from the skin—can improve their performance.

Methods

Ultrasounds of clinical T1/T2 tumors were reviewed. Distances of the tumor from the skin and from the nipple were measured. MSKCC and MDACC nomogram predictions and the AUC–ROC for each model were calculated. The added utility of the two variables was then examined using multiple logistic regression.

Results

Of 401 cancers studied, 79 (19.7 %) were node positive. The mean distance of tumors from the nipple in node-positive patients was 4.9 cm compared with 6.0 cm in node-negative patients (p = 0.0007). The mean distance of tumors from the skin was closer in node-positive cases (0.8 cm) versus node-negative cases (1.0 cm, p = 0.0007). The MSKCC and MDACC nomograms AUC–ROC values were 0.71 (95 % CI 0.64–0.77) and 0.74 (95 % CI 0.68–0.81). When adjusted for the MSKCC predicted probability, addition of both distance from nipple (p = 0.008) and distance from skin (p = 0.02) contributed significantly to prediction of nodal positivity and improved the AUC–ROC to 0.75 (95 % CI 0.70–0.81). Similarly, distance from nipple (p = 0.002), but not distance from skin (p = 0.09), added modestly to the MDACC nomogram performance (AUC 0.77; 95 % CI 0.71–0.83).

Conclusions

Distance of tumor from the nipple and from the skin are important variables associated with nodal positivity. Adding these to established nomograms improves prediction of nodal positivity.