Mammalian oocytes store proteins for the early embryo on cytoplasmic lattices

Mammalian oocytes are filled with poorly understood structures called cytoplasmic lattices. First discovered in the 1960s and speculated to correspond to mammalian yolk, ribosomal arrays, or intermediate filaments, their function has remained enigmatic to date. Here, we show that cytoplasmic lattices are sites where oocytes store essential proteins for early embryonic development. Using super-resolution light microscopy and cryoelectron tomography, we show that cytoplasmic lattices are composed of filaments with a high surface area, which contain PADI6 and subcortical maternal complex proteins. The lattices associate with many proteins critical for embryonic development, including proteins that control epigenetic reprogramming of the preimplantation embryo. Loss of cytoplasmic lattices by knocking out PADI6 or the subcortical maternal complex prevents the accumulation of these proteins and results in early embryonic arrest. Our work suggests that cytoplasmic lattices enrich maternally provided proteins to prevent their premature degradation and cellular activity, thereby enabling early mammalian development.

Weight loss with very-low-calorie diet and cardiovascular risk factors in moderately obese women: one-year follow-up study including ambulatory blood pressure monitoring

OBJECTIVE

The beneficial effects of weight loss with a very-low-calorie diet (VLCD) on cardiovascular risk factors have been reported at the end of energy restriction. As the effects, especially on blood pressure, may not remain constant during weight maintenance, we studied the longer-term effects of weight loss on 24h ambulatory blood pressure (ABP), lipids, glucose and insulin.

DESIGN

Prospective study of a 17-week weight loss programme containing an eight-week VLCD period and follow-up visit at one-year.

SUBJECTS

Twenty-nine moderately obese, normotensive or mildly hypertensive women. The mean +/- s.d. body mass index (BMI) was 36.0 +/- 2.6 kg/m2 and mean age 40.3 +/- 8.3 y.

RESULTS

In the last week of the VLCD, the mean (s.d.) weight loss was 12.4 +/- 3.3 kg (P < 0.001), at the end of the programme 15.1 +/- 4.4 kg (P < 0.001 vs baseline), and at one-year follow-up 10.7 +/- 7.6 kg (P < 0.001 vs baseline). Mean 24 h ABP decreased 8.0/4.6 mmHg (P < 0.001 for both) on the last week of the VLCD, at the end of the programme, the systolic ABP decrease was 4.7 mmHg (P < 0.01 vs baseline) and diastolic 2.1 mmHg (not statistically significant (NS) vs baseline). At one-year follow-up, the mean systolic ABP decrease was 4.1 mmHg (P < 0.01 vs baseline) and mean diastolic 3.0 mmHg (P < 0.05 vs baseline). Sodium excretion decreased 55 mmol/24 h in the last VLCD week (P < 0.01) and returned to baseline after that. At the one-year follow-up, beneficial changes, compared with baseline, were observed in mean serum glucose (-0.28 mmol/l, P < 0.05), triglyceride (-0.35 mmol/l, P < 0.01) and HDL cholesterol (+0.16 mmol/l, P < 0.001).

CONCLUSIONS

This weight loss programme with a VLCD enabled obese subjects to lose weight and decrease cardiovascular risks. Despite some regain in weight during follow-up, the beneficial effects were overall maintained over the year. Sodium intake tended to increase during follow-up. Information on sodium restriction should be included in weight loss programmes.

Two year maintenance of weight loss after a VLCD and behavioural therapy for obesity: correlation to the scores of questionnaires measuring eating behaviour

OBJECTIVE

To investigate changes in weight, Three Factor Eating Questionnaire and Binge eating scores during a two-year period from the start of a VLCD (Nutrilett) and behavioural modification therapy for obesity.

DESIGN

Prospective study of a 17-weeks weight loss programme with one- and two-year follow-up visits.

SUBJECTS

62 healthy, overweight subjects without previous eating disorders. The mean (+/- SD) age 41 +/- 8 years and BMI 36.4 +/- 2.6 kg/m2.

MAIN OUTCOME MEASURES

Weight loss, Binge eating scale, Bulimic Investigatory Test and Three Factor Eating Questionnaire before and after therapy and at 1 and 2 year control visits.

RESULTS

The mean weight loss (+/- SD) at the end of the treatment was 14.9 +/- 4.6 kg (n = 59) and at the two-year control 5.8 +/- 7.6 kg (n = 57). After two years 20 (32%) patients had a weight loss of more than 10% (good result), 24 patients a weight loss of 0-10% of their initial weight (partial result) and 13 patients weighed more than before therapy (poor result). The mean binge eating, disinhibition and hunger scores decreased in all patients by the end of the therapy. At the end of two years these improvements in the scores were maintained in patients with a good result but the scores returned to the pretreatment levels in the patients with partial or poor result. The mean restraint scores increased in all patients after treatment and were maintained in those with a good or partial result.

CONCLUSIONS

VLCD combined with behaviour modification is a useful mode of therapy for obesity with low drop-out rate and majority (71%) of patients below pretreatment weight at the two-year control. One third of the patients succeeded to maintain positive changes in the scores measuring eating behaviour which was associated with sustained weight loss.

Caries prevalence in Turner's syndrome (45,X females)

Dental caries prevelance in permanent teeth (DFS) was studied in 50 patients with Turner's syndrome (45,X females) and 41 normal first-degree female relatives. Caries prevalence was lower in 45,X women than in controls, and this difference was more pronounced in the incisor region than in pre-molar and molar teeth.

Effects of sodium aurothiomalate on hyaluronic acid synthesis in normal and rheumatoid synovial fibroblast cultures

In studies with normal and rheumatoid synovial fibroblast cultures the effects of sodium aurothiomalate on the quantity and quality of hyaluronic acid were tested. This gold compound produced one clear effect: the molecular weight of hyaluronate produced by rheumatoid fibroblasts was increased (shifted towards normal) whereas the effects on the amounts of hyaluronic acid synthesized were small in both rheumatoid and control cultures. The importance of this finding in relation to the known beneficial effects of gold preparations in clinical medicine is discussed.

Dependence of collagen synthesis by embryonic chick tendon cells on the extracellular concentrations of glutamine

An agent in rheumatoid synovial fluid which stimulates collagen synthesis by embryonic chick tendon cells was identified as glutamine. The stimulating effect was observed only at a subnormal concentration of proline (0.02 mM). The concentration of glutamine in rheumatoid synovial fluid is about 2.5 mM but it falls rapidly during storage even at -20 degrees C. Collagen synthesis is shown to depend on the extracellular concentrations of glutamine and proline in addition to any connective tissue activating factors.

Connective tissue activation by synovial fluids and synovial-tissue extracts of rheumatoid arthritis patients

Prompted by Castor's investigations (4) on a connective-tissue-activating peptide (CTAP) we investigated the stimulative effect of synovial fluids and synovial-tissue extracts on the synthesis of collagen by incubated embryonic-chick tendon cells. The stimulative effect was greater with synovial-tissue extracts from more severe cases than with samples from patients having milder forms of the disease. There was no correlation between the stimulation by synovial fluids and synovial-tissue extracts from the same patient. The stimulative activity was lost at dialysis. A slight stimulation in the incorporation of glucosamine was also observed. Treatment of the patients with gold, chloroquine or steroids decreased the stimulating capacity. These effects seem to depend on factors different from those described by Castor. The differerences in the stimulant activity of samples from various groups cannot be entirely due to glutamine, which is one of the limiting nutrients of the embryonic-chick tendon cells.